HP 5890 Series II and HP 5890 Series II Plus Operating Manual HEWLETT

HP 5890 Series II and HP 5890 Series II Plus Operating Manual HEWLETT
HP 5890 Series II and
HP 5890 Series II Plus
Operating Manual
HEWLETT
PACKARD
Manual Part No.
05890-90260
Edition 8, November 1993
Printed in U.S.A.
Printing History
The information contained in this document may be revised without notice.
Hewlett-Packard makes no warranty of any kind with regard to this material,
including, but not limited to, the implied warranties of merchantability and fitness
for a particular purpose. Hewlett-Packard shall not be liable for errors
contained herein or for incidental, or consequential damages in connection
with the furnishing, performance, or use of this material.
No part of this document may be photocopied or reproduced, or translated to
another program language without the prior written consent of
Hewlett-Packard Company.
First edition—June 1989
Second edition—October 1989
Third edition—January 1990
Fourth edition—October 1990
Fifth edition—October 1991
Sixth edition—September 1992
Seventh edition—June 1993
Eighth edition—November 1993
Printed in U.S.A.
® Copyright 1993 by Hewlett-Packard Company
All Rights Reserved. Reproduction, adaptation, or translation without prior written
permission is prohibited, except as allowed under the copyright laws.
Safety Information
The HP 5890 Series II and HP 5890 Series II Plus are IEC (International
Electrotechnical Commission) Safety Class 1 instruments. This unit has been
designed and tested in accordance with recognized safety standards.
Whenever the safety protection of the HP 5890 Series II and HP 5890
Series II Plus have been compromised, disconnect the unit from all power
sources and secure the unit against unintended operation.
Safety Symbols
This manual contains safety information that should be followed by the user to
insure safe operation.
WARNING
A WARNING CALLS ATTENTION TO A CONDITION OR POSSIBLE SITUATION THAT COULD CAUSE INJURY TO THE USER.
A Caution calls attention to a condition or possible situation
that could damage or destroy the product or the user's work.
DECLARATION OF CONFORMITY
according to ISO/IEC Guide 22 and EN 45014
Manufacturer's Name:
Manufacturer's Address:
Hewlett-Packard Co.
Little Falls Site 4300
2850 Centerville Rd.
Wilmington, DE 19808
declares that the product
Gas Chromatograph
5890 Series II
002,211,221,552, 110
Product Name:
Model Number:
Product Option:
conforms to the following Product Specifications:
EMC:
Vfg 523/1969
VDE 0871 Class A
Safety:
IEC 348:1978 (Second Edition) / HD 401:1980
CSAC22.2NO. 151-M1986
UL 1262 (Third Edition)
Supplementary information:
1 The product was tested in a typical configuration, including 7673B and
bar code reader.
2 CSA Certified
3 ETL (NRTL) Listed
Wilmington, DE, USA, Feb 26, 1993
Liza Baffle, Quality Manager
Contents
Chapter 1: Getting Started
Installation Checklist
Daily Startup
Daily Shutdown
Chapter 2:
1-1
1-2
1-2
Installing Columns
Preparing Fused Silica Capillary Columns
2-2
Installing Split/Splitless Capillary Inserts
2-4
Preparing Packed Metal Columns
2-6
Installing 1/4- and 1/8-inch Metal Columns in Packed Inlets
2-8
Installing 1/4-in Glass Columns in Packed Inlets
2-10
Installing Capillary Columns in Packed Inlets
2-12
Installing Capillary Columns in Split/Splitless Capillary Inlets
2-14
Installing 1/4-in Metal Columns in Flame Ionization and Nitrogen-Phosphorus Detectors . 2-16
Installing 1/8-in Metal Columns in Flame Ionization and Nitrogen-Phosphorus Detectors . 2-18
Installing Capillary Columns in Flame Ionization and
Nitrogen-Phosphorus Detectors
2-20
Installing an 1/8-inch Metal Column in a Thermal Conductivity Detector
2-22
Installing a Capillary Column in a Thermal Conductivity Detector
2-24
Installing a 1/4-inch Glass Column in an Electron Capture Detector
2-26
Installing a Capillary Column in an Electron Capture Detector
2-28
Installing an 1/8-inch Metal Column in a Flame Photometric Detector
2-30
Installing a Capillary Column in a Flame Photometric Detector
2-32
Chapter 3: Setting Heated Zone Temperatures
Operating Limits for Heated Zones
Setting Oven Temperatures
Displaying Oven Temperature
Examples
Setting Oven Temperature to 200°C
Setting Oven Equilibration Time to 1 Minute
Setting the Oven Maximum to 350°C
Using Cryogenic Oven Cooling
Programming Oven Temperatures
Examples
3-3
3-4
3-4
3-5
3-5
3-5
3-5
3-6
3-8
3-9
Setting Inlet and Detector Temperatures
Displaying Inlet and Detector Temperature
Example
Setting Inlet Temperature to 200°C
Setting Detector Temperature to 200°C
Setting Auxiliary Temperatures
3-13
3-13
3-14
3-14
3-14
3-15
Chapter 4: Setting Inlet System Flow Rates
Measuring Flow Rates
Using a Bubble Flow Meter
Required Adapters for Measuring Flow Rates
Changing the Packed Inlet Row Ranges
Changing the Source Pressure
Setting the Packed Inlet Row with Septum Purge
Manual Flow Control:
Electronic Pressure Control:
Setting the Split/Splitless Capillary Inlet Row
Setting the Split Mode Row
Manual Row Control:
Electronic Pressure Control:
Setting the Splitless Mode Row
Manual Row Control:
Electronic Pressure Control:
Manual Purge Switching:
Automatic Purge Switching:
Displaying the Gas Row Rate
Designating Gas Type
Using the Internal Stopwatch
Chapter 5:
4-1
4-2
4-4
4-5
4-5
4-6
4-6
4-7
4-9
4-11
4-11
4-12
4-18
4-18
4-19
4-21
4-21
4-25
4-25
4-27
Operating Detector Systems
Displaying Detector Status
Turning a Detector On or Off
Monitoring Detector Output
Operating Detectors Using Electronic Pressure Control
Accessing Auxiliary Channels C through F
Zeroing the Pressure Channel
Setting Constant Pressure
Setting Pressure Ramps
Changing Pressure Ramps
Example of Setting Pressure Ramps
Verifying Pressure Ramps
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-9
5-10
5-11
Setting Capillary Makeup Gas Flow Rate
Exceptions to Makeup Gas Flow
If the Power Fails
Shutting Down Each Day
5-12
5-12
5-15
5-15
Operating the Flame Ionization Detector (FID)
Setting Up the FID for Operation
Setting the FID Flow for Packed Columns
Setting the FID Flow for Capillary Columns
Setting the Makeup Gas Flow Rate
Turning the FID On and Off
Igniting the FID Flame
5-16
5-17
5-19
5-21
5-26
5-27
5-28
Operating the Thermal Conductivity Detector (TCD)
Setting Up the TCD for Operation
Setting the TCD Flow for Packed Columns
Setting the TCD Row for Capillary Columns
Setting the TCD Carrier Gas Type
Setting the TCD Sensitivity
Turning the TCD On and Off
Inverting the TCD Polarity
Using Single-Column Compensation (SCC)
Displaying the Column Compensation Status
Initiating a Column Compensation Run
Assigning Column Compensation Data
5-29
5-30
5-30
5-31
5-33
5-34
5-35
5-35
5-36
5-37
5-38
5-40
Operating the Nitrogen-Phosphorus Detector (NPD)
Setting Up the NPD for Operation
Conditioning the NPD Active Element (Bead)
Setting the NPD Active Element (Bead) Power
Setting the NPD Row for Packed Columns
Setting the NPD Row for Capillary Columns
Turning the NPD On and Off
Optimizing the Performance of the NPD
Avoiding Contamination
Preserving the Lifetime of the Active Element
5-42
5-43
5-44
5-45
5-47
5-49
5-52
5-53
5-53
5-54
Operating the Electron Capture Detector (ECD)
Requirements for USA Owners
Introduction
General Considerations
Temperature Effects
Gases
Columns and Flow Rates
Background
Setting Up the ECD for Operation
Setting the Carrier/Makeup Gas Selection Switch
Setting the ECD Flow for Packed Columns
Setting the ECD Row for Capillary Columns
Testing for Contamination
Testing for Leaks
Testing for Radioactive Leaks (the Wipe Test)
5-56
5-57
5-58
5-59
5-59
5-59
5-60
5-60
5-60
5-61
5-62
5-63
5-66
5-67
5-67
Operating the Flame Photometric Detector (FPD)
Setting Up the FPD for Operation
Setting the FPD Flow for Packed Columns
Setting the FPD Flow for Capillary Columns
Turning the FPD On and Off
Igniting the FPD Flame
5-68
5-68
5-69
5-71
5-74
5-74
Chapter 6:
Controlling Signal Output
Assigning a Signal
Displaying or Monitoring a Signal
Zeroing Signal Output
Turning Zero Off/On
Setting Signal Attenuation
Turning Attenuation Off/On
Inverting TCD Signal Polarity
Using Instrument Network (INET)
6-2
6-5
6-7
6-8
6-9
6-12
6-12
6-14
Chapter 7:
Making a Run
Starting/Stopping a Run
INET Start/Stop Operation
Status LEDs
Using the Time Key
Using Single-Column Compensation
Displaying Column Compensation Status
Initiating a Column Compensation Run
Assigning Column Compensation Data
Using Instrument Network (INET)
Using Timetable Events
Turning Valves On/Off During a Run
Switching Signals During a Run
Changing TCD Sensitivity During a Run
Modifying Timetable Events
7-1
7-1
7-2
7-6
7-8
7-9
7-10
7-12
7-14
7-15
7-18
7-20
7-22
7-23
Chapter 8: Storing and Loading HP 5890 Series II Setpoints
Storing GC Setpoints
Loading GC Setpoints
8-1
8-2
Chapter 9: Controlling Valves
Turning Valves On/Off Manually
9-2
Chapter 10: Using Electronic Pressure Control
What Is Electronic Pressure Control?
Using Electronic Pressure Control with Inlets (EPC)
Using Electronic Pressure Control with Detectors (Auxiliary EPC)
Safety Shutdown for Electronic Pressure Control
What Happens During Electronic Pressure Control Safety Shutdown?
Summary Table of Safety Shutdown
Setting Inlet Pressure Using Electronic Pressure Control
Zeroing the Pressure
Setting Constant Flow Mode
Setting Inlet Pressure Programs
Checking Inlet Pressure Programs
Setting Pressure Using Auxiliary Electronic Pressure Control
How Do I Access Auxiliary Electronic Pressure Control?
Setting Constant Detector Pressure
Setting Detector Pressure Programs
Checking Detector Pressure Programs
10-1
10-2
10-2
10-4
10-4
10-5
10-6
10-6
10-8
10-9
10-11
10-12
10-13
10-14
10-15
10-16
Suggested Ranges for Operating Auxiliary Electronic Pressure Control
Using Electronic Pressure Control to Control Gas Flow
Accessing the Flow Parameter Displays
Selecting the Gas Type
Setting the Column Diameter
Setting the Column Length
Using Vacuum Compensation Mode
Using Constant Flow Mode for Inlets
Setting Mass Flow Rate for Inlets
Setting Inlet Flow Programs
Setting the Average Linear Velocity
Understanding Average Linear Velocity
Calculating Outlet Row
Setting the Average Linear Velocity
Determining the Corrected Column Length
Packed Column Considerations
Capillary Column Considerations
Optimizing Splitless Injection Using Electronic Pressure Control
Operating the Gas Saver Application for the Split/Splitless Inlet
What Is the Gas Saver Application?
What Are the Required Settings for Operation?
How Is the Gas Saver Application Configured?
How Does the Gas Saver Application Operate?
Zero the Channel
Enter the Carrier Gas Pressure
Enter the Column Parameters
Set the System to Operating Conditions
Set the System to Off-Hour Conditions
Recommended Flow Rates for Inlet Systems Using the Gas Saver Application
Additional Benefits of the Gas Saver Application
Using the External Sampler Interface
Which Configuration Should I Use?
Using the External Sampler Interface with an Inlet as a Heated Zone
Special Considerations
Using Valve Options
Which Valves Work Best with Auxiliary Electronic Pressure Control?
10-17
10-22
10-24
10-25
10-26
10-26
10-27
10-28
10-29
10-30
10-32
10-32
10-33
10-33
10-34
10-34
10-34
10-36
10-38
10-38
10-38
10-39
10-40
10-40
10-41
10-41
10-42
10-42
10-43
10-43
10-44
10-44
10-54
10-54
10-57
10-60
Appendix A
Pressure—Flow Relationships for Inlet and Auxiliary Electronic Pressure Control
Outlet Flow
Average Linear Velocity
Calculating Flow from Average Linear Velocity
Example 1—Inlet Pressure 4.6 psig
Example 2—Inlet Pressure 8.3 psig
Example 3—Inlet Pressure 14.3 psig
References
A-l
A-2
A-2
A-3
A-4
A-4
A-5
A-5
Contents
Chapter 1: Getting Started
Installation Checklist
Daily Startup
Daily Shutdown
1-1
1-2
1-2
1
Getting Started
Installation Checklist
This checklist will help you get your HP 5890 Series II into operation. All references are to the
HP 5890 Series II Manual Set.
Checklist
Location
1. Select a location for the instrument.
Site Prep and Installation, Chapter 1
2. Check the new instrument for damage
in shipment.
Site Prep and Installation, Chapter 2
3. Make sure everything is present.
Site Prep and Installation, Chapter 2
4. Place the instrument in position and
make all connections.
Site Prep and Installation, Chapter 2
5. Turn the instrument on.
Site Prep and Installation, Chapter 2
6. Install a column.
Operating, Chapter 2
7. Set the inlet system flow rate.
Operating, Chapter 4
8. Set appropriate heated zone temperatures.
Operating, Chapter 3
9. Set the detector system flow rates.
Operating, Chapter 5
10. Turn the detector on.
Operating, Chapter 5
11. The instrument is now ready to
make a run.
Operating, Chapter 7
Getting Started
1-1
Daily Startup
1. Check that the operating conditions are correct for your analysis. Make any changes that
are needed.
2. Reset the detector sensitivity if you lowered it overnight.
3. If you're using temperature programming, make a blank run (no sample) to clean out any
septum bleed or carrier gas impurities that might have accumulated in the column.
4. Start your analysis.
Daily Shutdown
1. In most cases, leave the detectors on and at operating temperature. This will avoid a long
equilibration time in the morning. You may want to reduce the sensitivity, particularly
with the TCD and NPD detectors, to prolong their lifetime.
2. Leave the carrier flow on to protect the column(s). For extended shut-down periods, cool
the oven to room temperature and then turn the carrier flow off.
3. Now is a good time to change the inlet septum if needed. Volatile material will be baked
out overnight. But keep the columns warm so that the baked-out material doesn't
accumulate on the column. You can generally expect 1- or 2-days use from a septum, but
this is reduced by high temperatures, many injections, dull or hooked needles, etc. It's
best to avoid trouble by changing them daily.
Getting Started
1-2
Contents
Chapter 2:
Installing Columns
Preparing Fused Silica Capillary Columns
Installing Split/Splitless Capillary Inserts
Preparing Packed Metal Columns
Installing 1/4- and 1/8-inch Metal Columns in Packed Inlets
Installing 1/4-inch Glass Columns in Packed Inlets
Installing Capillary Columns in Packed Inlets
Installing Capillary Columns in Split/Splitless Capillary Inlets
Installing 1/4-inch Metal Columns in Flame Ionization and
Nitrogen-Phosphorus Detectors
Installing 1/8-inch Metal Columns in Flame Ionization and
Nitrogen—Phosphorus Detectors
Installing Capillary Columns in Flame Ionization and Nitrogen-Phosphorus Detectors . . . .
Installing an 1/8-inch Metal Column in a Thermal Conductivity Detector
Installing a Capillary Column in a Thermal Conductivity Detector
Installing a 1/4-inch Glass Column in an Electron Capture Detector
Installing a Capillary Column in an Electron Capture Detector
Installing an 1/8-inch Metal Column in a Flame Photometric Detector
Installing a Capillary Column in a Flame Photometric Detector
2-2
2-4
2-6
2-8
2-10
2-12
2-14
2-16
2-18
2-20
2-22
2-24
2-26
2-28
2-30
2-32
2
Installing Columns
The HP 5890 Series II and Series II Plus (hereafter referred to as HP 5890) provide flexibility
in choices among inlets, columns, and detectors through use of liners and adapters, allowing
any standard column to be used without sacrificing performance. Additional flexibility is gained
through positions of inlets and detectors relative to each other and through the large internal
volume of the oven.
Note: The Series 530 \i columns supplied with the HP 5890 must be conditioned before use.
This is done by establishing a flow of carrier gas at 30 to 60 ml/min through the column while
the column is heated at 250°C for at least 4 hours. See Preventive Maintenance in the HP 5890
Series II Reference Manual for more information about conditioning columns.
New columns should be conditioned because they often contain volatile contaminants absorbed
from the air. It may also be necessary to condition a used column that has been stored for some
time without end caps or plugs to exclude air.
This section provides information required for proper column installation:
•
Liners and inserts
•
Preparing packed columns
•
Installing packed columns
•
Preparing capillary columns
•
Installing capillary columns
Installing Columns 2-1
Preparing Fused Silica Capillary Columns
Fused silica columns are inherently straight, so no straightening procedures are necessary. It IS
important, however, to have fresh ends of the column, free of burrs, jagged edges, and/or loose
particles of column, stationary phase, and/or material from a sealing ferrule or O-ring.
Therefore, whenever the column must be cut to provide fresh ends, use a suitable glass scribing
tool (HP ceramic column cutter, part number 5181-8836) to first score the column at the point
at which it is to be broken. This is done normally AFTER installing on the column, the column
nuts and ferrule (or O-ring) required for installation.
WARNING
WEAR SAFETY GLASSES TO PREVENT POSSIBLE EYE INJURY FROM
FLYING PARTICLES WHILE HANDLING, CUTTING, OR INSTALLING
GLASS OR FUSED SILICA CAPILLARY COLUMNS. ALSO OBSERVE
CAUTION IN HANDLING CAPILLARY COLUMNS TO PREVENT SKIN
PUNCTURE WOUNDS.
BECAUSE OF THEIR GREATER RELATIVE RIGIDITY, THESE
PRECAUTIONS ARE ESPECIALLY IMPORTANT IN HANDLING
HEWLETT-PACKARD SERIES 530 \i CAPILLARY COLUMNS.
Installing Columns 2-2
Score
Break Point
Ferrule
Column Nut
I
Preparing Fused Silica Capillary Columns
Installing Columns 2-3
Installing Split/Splitless Capillary Inserts
A specific inlet insert is required, depending upon the particular sampling mode. Specific
sampling modes include:
•
Split, for major-component analyses
•
Purged splitless, for trace-component analyses
WARNING
EXERCISE CARE! THE OVEN, AND/OR INLET, OR DETECTOR
FITTINGS MAY BE HOT ENOUGH TO CAUSE BURNS.
If operating in split mode, carrier gas pressure must be reduced before
opening the inlet. If not done, pressure may blow insert packing out of
the inlet, altering its characteristics. Pressure is reduced at the column
head pressure regulator for the inlet.
1. In handling the insert, avoid contaminating its surface (particularly its interior).
2. Remove the insert retainer nut. The septum retainer nut need not be removed from the
insert retainer nut assembly.
3. Using tweezers, forceps, or similar tool, remove any insert already in place.
4. Inspect the new insert to be installed: For a split mode insert, the end with the mixing
chamber and packing is inserted first into the inlet.
5. Place a graphite or silicone O-ring on the insert, about 2 to 3 mm from its top end.
6. Replace the insert retainer nut, tightening it to FIRM finger-tightness to form a leak-free
seal. Do not overtighten.
Installing Columns 2-4
Installing Split/Splitless Capillary Inserts
Installing Split/Splitless Capillary Inserts
Installing Columns 2-5
Preparing Packed Metal Columns
Packed metal columns are installed similarly at both the inlet and detector. To minimize
unswept (dead) volume column inside the inlet or detector fitting, it is recommended that
ferrule(s) be preset and locked onto the column such that the end of the column is approximately flush with the end of the front ferrule (see figure at the top of next page).
If not already installed, follow the procedure below to install NEW swage-type nut and ferrules.
For metal columns with ferrules already installed and set, proceed to instructions for installing
metal columns in this section.
To insure the correct column position, a spacer may be made from a piece of Teflon tubing:
1. According to the column to be installed (1/8 or 1/4 inch), secure an appropriate NEW
male swage-type fitting in a bench vice.
2. Slide a NEW, brass, swage-type nut, rear ferrule, and front ferrule onto a piece of Teflon
tubing (1/8 or 1/4 inch). If necessary, use a razor or sharp knife to cut the end of the
tubing to present a flat, smooth end.
3. Fully insert the Teflon tubing, ferrules, and nut into the vise-held swage-type fitting.
Tighten the nut 3/4-turn past finger-tight to set the ferrules on the tubing. Then remove
the assembly from the male fitting.
4. Using a razor knife, cut off the end of the tubing extending beyond the front-most ferrule.
Insert the piece into the vise-held swage-type fitting.
This piece of tubing is now a spacer, insuring that when new ferrules are set onto a column, the
column end will be correctly positioned with respect to the end of the front-most ferrule. The
male fitting and spacer should be kept on hand to be used whenever new ferrules are being
installed on a column.
5. Install a NEW swage-type nut and ferrule(s) onto the column.
6. Fully insert the column with its nut and ferrules into the vise-held fitting.
7. First tighten the nut finger-tight. Use a wrench to tighten the column nut an additional
1- and -1/4 turns for 1/4-inch columns, or 3/4-turn for 1/8-inch columns.
8. Unscrew the column nut from the vise-held fittings, and remove the column. Ferrules
should now be set in place on the column, with the column correctly positioned.
Installing Columns 2-6
Recommended
Not Desirable
(May cause problems due
to dead volume)
Minimum Exposed
Column
Recommended Location for Ferrules on Packed Columns
Exposed Teflon Tube
to be Cut
Cut Spacer
Spacer Installed
in Fitting
Teflon Tubing
Making a Teflon Spacer
Preparing Packed Metal Columns
Installing Columns 2-7
Installing 1/4- and 1/8-inch Metal Columns in Packed Inlets
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the liner/adapter.
2. Insert the adapter straight into the inlet base as far as possible.
3. Holding the adapter in this position, tighten the nut finger-tight.
4. Use a wrench to tighten the nut an additional 1/4-turn.
To install new swage-type nut and ferrules on the column, follow the procedure Preparing
Packed Metal Columns, earlier in this section. For metal columns with ferrules already
installed, continue with step 5.
5. Install the column into the inlet by tightening the column nut, assuming ferrule(s) are
already set (locked) onto the column (see Preparing Packed Metal Columns in this section).
Generally an additional 1/4-turn past finger-tight is sufficient for 1/8-inch columns. For
1/4-inch columns, an additional 3/4-turn is usually sufficient.
Use two wrenches in opposition, one on the column nut and the other on the liner body,
to prevent rotation of the liner while tightening the column nut.
Installing Columns 2-8
1/4-inch Metal Column, Packed Inlet
1/8-inch Metal Column, Packed Inlet
Inlet Fitting
Inlet Fitting
1/4-inch Ferrule
/
\
1/4-inch Metal Ferrule
Back Ferrule
1
1/4-inch Nut
1/4-inch Nut
1/8-inch Liner
1/4-inch Column
ra
Front Ferrule
Back Ferrule
1/8-inch Nut
1/8-inch Column
Using Two Wrenches in Opposition to Tighten Column Fittings
Installing 1/4 and 1/8-inch Metal Columns in Packed Inlets
Installing Columns 2-9
Installing 1/4-inch Glass Columns in Packed Inlets
At the inlet end, there must be enough column left empty to prevent an inserted syringe needle
from contacting either the glass wool plug or column packing (at least 50 mm).
At the detector end, there must be at least a 40-mm empty section to prevent the bottom end of
the jet from touching either column packing or glass wool plug.
Because they are rigid, 1/4-inch packed glass columns must be installed simultaneously at both
the inlet and the detector. The procedure is identical at either end. For information on
detector column installation, refer to the appropriate section depending on the detector being
used.
Glass columns can be installed with either O-rings or nonmetallic ferrules. For O-ring
installation, we recommend using one O-ring with a front metal ferrule, reversed to provide a
flat surface for it to seal against.
Using the figures on the next page as a guide:
1. Assemble a brass nut, reversed metal ferrule, and O-ring onto both ends of the column.
If desired, an extra O-ring may be placed on the column before the nut. This protects the
column by preventing the nuts from dropping into the coiled portion of the column.
2. Insert the column into both the inlet and detector as far as possible. To clear the floor of
the oven, it may be necessary to start the longer end of the column into the inlet at a slight
angle.
3. Withdraw the column about 1 to 2 mm and tighten both column nuts finger-tight; the
degree to which the nut is tightened further depends upon the type of ferrule used:
•
For O-rings, finger-tight is usually sufficient.
•
For Vespel or graphite ferrules, raise the inlet, detector, and oven to operating
temperature, then use a wrench to tighten an additional 1/2-turn. Tighten further as
necessary to prevent leakage.
CAUTION
Overtightening the column nut may shatter the column.
Installing Columns 2-10
1/4-inch Column, Packed Inlet
u
Inlet Fitting
Graphite 0-ring
Reversed Brass Ferrule
i
1
1/4-inch Nut
Silicone 0-ring
Recommended
Silicone O-ring
Graphite, Vespel,
or
Graphitized Vespel
Ferrule
Graphite O-ring
I
II
ft U
I
I
a
=
•I
I
17
1
I
Alternative Installation Methods
Installing 1/4-inch Glass Columns in Packed Inlets
Installing Columns 2-11
Installing Capillary Columns in Packed Inlets
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the liner/adapter.
2. Install a glass insert into the liner/adapter.
3. Insert the liner/adapter straight into the inlet as far as possible.
4. Holding the liner/adapter in this position, tighten the nut finger-tight.
5. Use a wrench to tighten the nut an additional 1/4-turn.
Hewlett-Packard capillary columns are wound on wire frames and mount on a pair of
brackets that slip into slots at the top of the oven interior.
The bracket has two positions from which to hang the column wire frame. Depending
upon frame diameter, use the position that best centers the column in the oven. Column
ends should come off the bottom of the frame, making smooth curves to inlet and detector
fittings. Avoid allowing any section of the column itself to come in contact with oven
interior surfaces.
6. Install on the column, a column nut (HP part no. 18740-20870) and ferrule. Note that
either a 1.0- or 0.5-mm id graphite ferrule may be used depending upon column outer
diameter.
Inserting the column through the nut and ferrule may contaminate the end of the column.
Prepare a fresh column end by the instructions given in Preparing Fused Silica Capillary
Columns in this section.
7. Position the column so it extends less than 2.0 mm from the end of the ferrule and column
nut (threaded end). Mark the column at a point even with the bottom of the nut
(hexagonal end). Typewriter correction fluid is a good marking material.
8. Insert column, ferrule, and nut straight into the inlet base. While maintaining the mark on
the column so as to be even with the bottom of the column nut, tighten the nut to
finger-tightness, then 1/4-turn more using a wrench.
9. While holding the spring to the right, slide the capillary liner insulation cup up over the
capillary nut. The insulation at the top of the cup should fit flush against the roof of the
oven.
10. Release the spring into the groove in the inlet liner.
Installing Columns 2-12
Column Hanger Position
Capillary Column, Packed Inlet
Inlet Fitting
c
n,
8
Glass Insert
Liner
Marking the Column Position
1/4-inch
Ferrule
Liner
Retainer
Nut
-4 -
-2 cra_
About 2 mm
Graphite
Ferrule
0 I
Capillary
Column
Nut
Capillary
Column
Capillary Liner
Insulation Cup
Paint Mark
Installing Capillary Columns in Packed Inlets
Installing Columns 2-13
Installing Capillary Columns in Split/Splitless Capillary Inlets
A specific inlet insert is required depending upon the particular sampling mode, split or
splitless. See "Installing Split/Splitless Capillary Inlet Inserts" in the this chapter, if not already
installed.
The following installation procedure assumes that the inlet is prepared properly to receive the
capillary column (e.g., that the correct insert is already installed).
Hewlett-Packard capillary columns are wound on wire frames and mount on a pair of brackets
that slip into slots at the top of the oven interior.
The bracket has two positions from which to hang the column wire frame. Depending upon
frame diameter, use the position that best centers the column in the oven. Column ends should
come off the bottom of the frame, making smooth curves to inlet and detector fittings. Avoid
allowing any section of the column itself to come in contact with oven interior surfaces.
Using the figures on the next page as a guide:
1. Install on the column a column nut (HP part no. 18740-20870) and ferrule. Note that
either a 1.0- or 0.5-mm id graphite ferrule may be used depending upon column outer
diameter.
Inserting the column through the nut and ferrule may contaminate the end of the column.
Prepare a fresh column end following instructions given in Preparing Fused Silica Capillary
Columns in this section.
2. Position the column so it extends approximately 4 to 6 mm from the end of the ferrule and
column nut (threaded end). Mark the column at a point even with the bottom of the nut
(hexagonal end). Typewriter correction fluid is a good marking material.
3. Insert column, ferrule, and nut straight into the inlet base. While maintaining the mark on
the column so as to be even with the bottom of the column nut, tighten the nut to
finger-tightness, then 1/4-turn more using a wrench.
Installing Columns 2-14
Column Hanger Position
Capillary Column
Split/Splitless Capillary Inlet
Marking the Column Position
Inlet Fitting
H
Graphite Ferrule
-4 Capillary Column Nut
— 2 ->
Approx. 4 to 6 mm
Capillary Column
0 =
Paint Mark
Installing Capillary Columns in Split/Splitless Capillary Inlets
Installing Columns 2-15
Installing 1/4-Inch Metal Columns in Flame lonization and
Nitrogen-Phosphorus Detectors
Nitrogen-Phosphorus Detectors: To avoid contamination of the active element upon receipt, do
not remove the seals until ready to connect the column and operate the detector. Failure to
observe this simple procedure may reduce the collector's effectiveness or possibly ruin the
active element.
To install new swage-type nut and ferrules on the column, follow the procedure Preparing
Packed Metal Columns, earlier in this section. For metal columns with ferrules already
installed, continue.
Using the figures on the next page as a guide:
Install the column into the inlet by tightening the column nut, assuming ferrule(s) are already
set (locked) onto the column (see Preparing Packed Metal Columns in this chapter). Generally
an additional 3/4-turn is usually sufficient.
Installing Columns 2-16
1/4-inch Packed Metal Column, FID/NPD
Inlet Fitting
o
Front Ferrule
Back Ferrule
1
1/4-inch Nut
1/4-inch Column
Installing 1/4-inch Metal Columns in an FID and NPD
Installing Columns 2-17
Installing 1/8-inch Metal Columns in Flame lonization and
Nitrogen-Phosphorus Detectors
Nitrogen-Phosphorus Detectors: To avoid contamination of the active element upon receipt,
do not remove the seals until ready to connect the column and operate the detector. Failure to
observe this simple procedure may reduce the collector's effectiveness or possibly ruin the
active element.
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the liner/adapter.
2. Insert the adapter straight into the detector base as far as possible.
3. Holding the adapter in this position, tighten the nut finger-tight.
4. Use a wrench to tighten the nut an additional 1/4-turn.
5. Install the column into the inlet by tightening the column nut, assuming ferrule(s) are
already set (locked) onto the column (see Preparing Packed Metal Columns in this section).
Generally an additional 1/4-turn is usually sufficient.
Use two wrenches in opposition, one on the column nut and the other on the liner body,
to prevent rotation of the liner while tightening the column nut.
Installing Columns 2-18
1/8-inch Packed Metal Column,
FID/NPD
Detector Fitting
1/4-inch Ferrule
I
1/4-inch Nut
Using Two Wrenches in Opposition to Tighten
Column Fittings
1
1
1/8-inch Adapter
«i
ro
Front Ferrule
Back Ferrule
1/8-inch Nut
1/8-inch Column
Installing 1/8-inch Metal Columns in an FID and NPD
Installing Columns 2-19
Installing Capillary Columns in Flame lonization and
Nitrogen-Phosphorus Detectors
Nitrogen-Phosphorus Detectors: To avoid contamination of the active element upon receipt, do
not remove the seals until ready to connect the column and operate the detector. Failure to
observe this simple procedure may reduce the collector's effectiveness or possibly ruin the
active element.
Assuming that the 0.011-inch capillary jet (HP part no. 19244-80560) is installed (if not, see
Chapter 9, "Preventive Maintenance" in the HP 5890 Reference Manual), proceed as follows:
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the liner/adapter.
2. Insert the adapter straight into the detector base as far as possible.
3. Holding the adapter in this position, tighten the nut finger-tight.
4. Use a wrench to tighten the nut an additional 1/4-turn.
5. Install on the column, a column nut (HP part no. 18740-20870) and ferrule. Note that
either a 1.0- or 0.5-mm id graphite ferrule may be used depending upon column outer
diameter.
Inserting the column through the nut and ferrule may contaminate the end of the column.
Prepare a fresh column end following instructions given in "Preparing Fussed Silica
Capillary Columns" in this chapter.
6. GENTLY insert the column as far as possible into the detector (about 40 mm) until it
bottoms; do not attempt to force it further. Follow it with the ferrule and column nut.
7. Tighten the nut finger-tight, withdraw the column approximately 1 mm, and then tighten
the nut an additional 1/4-turn with a wrench.
8. Leak-test the installation at the column nut, both at ambient temperature and with the
oven, inlet(s), and detector(s) at operating temperatures. If necessary, tighten fitting(s)
further only enough to stop leakage.
Leak-detection fluids often leave contaminating residues. After each
application, the area checked should be rinsed with CH 3 OH (methanol)
and allowed to dry.
Installing Columns 2-20
Capillary Column, FID/NPD
Detector Fitting
1/4-inch Ferrule
1
O
1/4-inch Nut
Capillary Column Adapter
Ferrule
Capillary Column Nut
Capillary Column
Installing Capillary Columns in FID and NPD
Installing Columns 2-21
Installing an 1/8-inch Metal Column in a
Thermal Conductivity Detector
To install new swage-type nut and ferrules on the column, follow the procedure Preparing
Packed Metal Columns, earlier in this chapter. For columns with ferrules already installed,
continue.
Using the figures on the next page as a guide:
Install the column into the inlet by tightening the column nut, assuming the ferrule(s) are
already set onto the column. An additional 1/4-turn is usually sufficient.
Installing Columns 2-22
1/8-inch Packed Metal Column, TCD
Detector Fitting
LJ
Front Ferrule
Back Ferrule
1/8-inch Nut
1/8-inch Column
Installing a 1/8-inch Metal Column in a Thermal Conductivity Detector
Installing Columns 2-23
Installing a Capillary Column in a
Thermal Conductivity Detector
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the liner/adapter.
2. Insert the adapter straight into the detector base as far as possible.
3. Holding the adapter in this position, tighten the nut finger-tight.
4. Use a wrench to tighten the nut an additional 1/4-turn.
5. Install on the column, a column nut (HP part no. 18740-20870) and ferrule. Note that
either a 1.0- or 0.5-mm id graphite ferrule may be used depending upon column outer
diameter.
Inserting the column through the nut and ferrule may contaminate the end of the column.
Prepare a fresh column end following instructions given in Preparing Fused Silica Capillary
Columns in this chapter.
6. GENTLY insert the column as far as possible into the detector until it bottoms; do not
attempt to force it further. Follow it with the ferrule and column nut.
7. Tighten the nut finger-tight, withdraw the column approximately 1 mm, and then tighten
the nut an additional 1/4-turn with a wrench.
8. Leak-test the installation at the column nut, both at ambient temperature and with the
oven, inlet(s), and detector(s) at operating temperatures. If necessary, tighten fitting(s)
further only enough to stop leakage.
Leak-detection fluids often leave contaminating residues. After each
application, the area checked should be rinsed with CH 3 OH (methanol)
and allowed to dry.
Installing Columns 2-24
Capillary Column
with Makeup Gas, TCD
Detector Fitting
Ferrule
P.
1/8-inch Nut
TCD Makeup Gas
Adapter
Ferrule
Capillary Column Nut
Capillary Column
Installing a Capillary Column in a Thermal Conductivity Detector
Installing Columns 2-25
Installing a 1/4-inch Glass Column in an
Electron Capture Detector
Because they are rigid, 1/4-inch packed glass columns must be installed simultaneously at both
the inlet and the detector. The procedure is identical at either end. For information on inlet
column installation, refer to the appropriate chapter depending on the inlet being used.
Glass columns can be installed with either O-rings or nonmetallic ferrules. For O-ring
installation, we recommend using one O-ring with a front metal ferrule, reversed to provide a
flat surface for it to seal against.
Using the figures on the next page as a guide:
1. Assemble a brass nut, reversed metal ferrule, and O-ring onto both ends of the column.
If desired, an extra O-ring may be placed on the column before the nut. This protects the
column by preventing the nuts from dropping into the coiled portion of the column.
2. Insert the column into both the inlet and detector as far as possible. To clear the floor of
the oven, it may be necessary to start the longer end of the column into the inlet at a slight
angle.
3. Withdraw the column about 1 to 2 mm and tighten both column nuts finger-tight; the
degree to which the nut is tightened further depends upon the type of ferrule used:
•
For O-rings, finger-tight is usually sufficient.
•
For Vespel or graphite ferrules, raise the inlet, detector, and oven to operating
temperature, then use a wrench to tighten an additional 1/2-turn. Tighten further as
necessary to prevent leakage.
CAUTION
Overtightening the column nut may shatter the column.
Installing Columns 2-26
1/4-inch Packed Glass Column, ECD
Detector Fitting
Graphite O-ring
§
Reversed Brass Ferrule
1
1
1/4-inch Nut
Silicone O-ring
Recommended
Silicone O-ring
Graphite O-ring
I
I
11
I
Graphite, Vespel,
or
Graphitized Vespel
Ferrule
•!+ -l-l.
I
\
I
I
1
II
Mi
11
I
1
II
1/4-inch Packed Glass Columns, Alternative Installation Methods
Installing a 1/4-inch Glass Column in an Electron Capture Detector
Installing Columns 2-27
Installing a Capillary Column in an Electron Capture Detector
Using the figures on the next page as a guide:
1. Remove the cap of the makeup gas adapter.
2. Install a fused silica liner in the bottom half of the adapter.
3. Replace the cap of the makeup gas adapter. Tighten the cap hand-tight.
4. Insert the ECD adapter straight into the detector as far as possible and tighten the nut
finger-tight.
5. Use a wrench to tighten the nut an additional 1/4-turn.
6. Install on the column a column nut (HP part no. 18740-20870) and ferrule. Note that
either a 1.0- or 0.5-mm id graphite ferrule may be used depending upon column outer
diameter.
Inserting the column through the nut and ferrule may contaminate the end of the column.
Prepare a fresh column end following instructions given in "Preparing Fused Silica
Capillary Columns" in this chapter.
7. Measure 75 mm from the end of the column and mark the column. Typewriter correction
fluid is a good marking material. Gently insert the column into the detector followed by
the ferrule and column nut. Tighten the nut finger-tight. Position the column so the
75-mm mark is even with the end of the column nut. Tighten the nut an additional
1/4-turn with a wrench.
Installing Columns 2-28
Capillary Column
with Makeup Gas, ECD
Detector Fitting
1/4-inch Ferrule
n
Cap
1/4-inch Nut
ECD Capillary
Column Adapter
Fused Silica Liner
Ferrule
Capillary Column Nut
T
75 mm
Capillary Column
ECD Capillary
Column Adapter
1
I
Paint Mark
1.
Installing a Capillary Column in an Electron Capture Detector
Installing Columns 2-29
Installing an 1/8-inch Metal Column in a
Flame Photometric Detector
To install new swage-type nut and ferrules on the column, follow the procedure Preparing
Packed Metal Columns, earlier in this chapter. For columns with ferrules already installed,
continue.
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the liner/adapter.
2. Insert the adapter straight into the detector base as far as possible.
3. Holding the adapter in this position, tighten the nut finger-tight.
4. Use a wrench to tighten the nut an additional 1/4-turn.
5. Install the column into the inlet by tightening the column nut assuming ferrule(s) are
already set (locked) onto the column (see "Preparing Packed Metal Columns" in this
chapter). An additional 1/4-turn is usually sufficient.
Use two wrenches in opposition, one on the column nut and the other on the liner body,
to prevent rotation of the liner while tightening the column nut.
Installing Columns 2-30
1/8-inch Packed Metal Column, FPD
Detector Fitting
Using Two Wrenches in Opposition to Tighten
Column Fittings
1/4-inch Ferrule
1/4-inch Nut
1/8-inch Liner
rQ
Front Ferrule
Back Ferrule
1/8-inch Nut
1/8-inch Column
Installing an 1/8-inch Metal Column in a Flame Photometric Detector
Installing Columns 2-31
Installing a Capillary Column in a Flame Photometric Detector
Using the figures on the next page as a guide:
1. Assemble a brass nut and graphite ferrule onto the FPD capillary column adapter.
2. Insert the FPD adapter straight into the detector as far as possible and tighten the nut
finger-tight.
3. Use a wrench to tighten the nut an additional 1/4-turn.
4. Install on the column a column nut and ferrule. Note that either a 1.0- or 0.5-mm id
graphite feirule may be used depending upon column outer diameter.
Inserting the column through the nut and ferrule may contaminate the end of the column.
Prepare a fresh column end following instructions given in "Preparing Fused Silica
Capillary Columns" in this chapter.
5. Measure 162 mm from the end of the column and mark the column. Typewriter correction
fluid is a good marking material. Gently insert the column into the detector followed by
the ferrule and column nut. Tighten the nut finger-tight. Position the column so the
162-mm mark is even with the end of the column nut. Tighten the nut an additional
1/4-turn with a wrench.
This height may be optimized higher or lower depending on sample type and detector flow
rates. If the column is too high, it can be exposed to the detector flame. If the column is
too low, the sample can be exposed to some hot stainless steel which can result in slight
peak tailing.
Installing Columns 2-32
Brass Nut
FPD Capillary
Column Adapter
Graphite Ferrule
Capillary
Column Nut
162 mm
Paint Mark
Installing a Capillary Column in a Flame Photometric Detector
Installing Columns 2-33
Contents
Chapter 3:
Setting Heated Zone Temperatures
Operating Limits for Heated Zones
Setting Oven Temperatures
Displaying Oven Temperature
Examples
Setting Oven Temperature to 200°C
Setting Oven Equilibration Time to 1 Minute
Setting the Oven Maximum to 350°C
Using Cryogenic Oven Cooling
Programming Oven Temperatures
Examples
Setting Inlet and Detector Temperatures
Displaying Inlet and Detector Temperature
Example
Setting Inlet Temperature to 200°C
Setting Detector Temperature to 200°C
Setting Auxiliary Temperatures
3-3
3-4
3-4
3-5
3-5
3-5
3-5
3-6
3-8
3-9
3-13
3-13
3-14
3-14
3-14
3-15
3
Setting Heated Zone Temperatures
Oven temperature, and temperatures of up to five separate heated zones (detectors, inlets,
and/or heated valves), are controlled through keys shown.
TEMPERATURE CONTROL KEYS
Oven Control
OVEN
TEMP
INIT
VALUE
INIT
TIME
FINAL
VALUE
RATE
OVEN
MAX
INJA
TEMP
INJB
TEMP
DETA
TEMP
DETB
TEMP
+
4
'
EQUIB
TIME
FINAL
TIME
1 illli
Heated Zone Control
In these cases, BOTH current setpoint value AND current monitored value are displayed by
pressing the appropriate temperature control key. For example, the next figure shows typical
displays obtained by pressing the [ OVENTEMP~"| key.
Setting Heated Zone Temperatures 3-1
Typical Display, Setpoint And Current Value
ACTUAL
27*
SETPOINT
350
Note that the ACTUAL value is a measured quantity, while the SETPOINT value is userdefined: In this example, the setpoint value for oven temperature might recently have been
changed from 250 to 350 °C, and the oven is now heating to the new setpoint. Given sufficient
time for equilibration, ACTUAL and SETPOINT values become equal.
In addition to
in defining setpoint values,
sequences:
>! - 1,1 • > I CLEAR > , anHl ENTER 1> which are used
OFF l [ A l } a nd 1 B \ are used in certain specific key
0N
1 and I°FFI add convenience in being able to switch on or off the oven,
and/or heated zones, without losing their current setpoint values.
Keys 1 A I and I B I are used in key sequences defining a multiple-ramp oven
temperature program: I A 1 as part of key sequences defining parameters for the
second ramp, 1 B I as part of key sequences defining parameters for the third ramp.
Setting Heated Zone Temperatures 3-2
Operating Limits for Heated Zones
Valid Setpoint Ranges For Temperature Control Keys
Valid
Setpoint Range
Key
In
Increments of
Function
Oven Control
- 8 0 to 450
re
re
0 to 650.00
0.01 minute
Oven Control
0to70
0.1 /minute
Oven Control
[
OVEN TEMP
1
- 8 0 to 450
[
INITTEMP
1
[
INITTIME
1
Oven Control
[
FINAL TEMP
1
- 8 0 to 450
re
Oven Control
[
FINAL TIME
^
0 to 650.00
0.01 minute
Oven Control
[
OVEN MAX
^1
70 to 450
re
Oven Control
[
EQUIBTIME
1
0 to 200.00
0.01 minute
Oven Control
[
INJATEMP
1
0 to 400
Zone Control
[
INJ B TEMP
1
0 to 400
[
DETATEMP
1
[
DETBTEMP
1
0 to 400*
re
re
re
re
Zone Control
[
AUXTEMP
1
o to 400
re
Zone Control
NOTE:
0 to 400*
Zone Control
Zone Control
TOTA _ run time will not exceed 650.00 minutes regardless of values entered
f o r C INITTIME 1 f RATE ) a n d f FINAL TIME 1
*The valid setpoint range for a flame ionization detector is 0 to 450°C.
Setting Heated Zone Temperatures 3-3
Setting Oven Temperatures
Oven temperature may be controlled anywhere within the range of — 80 °C (with cryogenic
cooling using liquid N2) through 450CC in increments of 1°C.
Oven temperature control keys include:
OVEN TEMP
To enter a constant temperature for the oven
EQUIBTIME
To enter a time for oven temperature to equilibrate
whenever oven temperature is modified
(Equilibration time begins when the actual oven temperature comes within 1°C of the oven temperature setting.)
OVEN MAX
To set an oven temperature maximum limit
Displaying Oven Temperature
Press [
OVEN TEMP
1 to display the current oven temperature.
Sample Display =
OVEN TEMP 60
The oven is switched on with key sequence: [
OVEN TEMP
60 {orOJFf)
1 [ ON \ 1
ENTER 1
The oven is also switched on by entering a new setpoint value; the new value replaces OFF or
the previous value.
Setting Heated Zone Temperatures 3-4
Examples
Setting Oven Temperature to 200 C
Current oven temp = 100 °C
Display =
Press:
QVBI TEMP
100
100
C OVEN TEMP
The oven temperature will change from 100°C to 200 °C and stabilize.
Setting Oven Equilibration Time to 1 Minute
Press:
[ EQUIBTIME J
[[ 1
1 \\
[[ •• \\
0 \
[[ 0
| 0
The oven equilibration time will be 1 minute.
Setting the Oven Maximum to 350 C
Press:
P ^^S i j s l
[
OVEN MAX"""!
1 3 1 1 5 11
The maximum temperature the oven can be set to is 350°C.
The HP 5890 SERIES II verifies oven setpoints as they are entered; an appropriate message is
displayed when an entered setpoint is inconsistent with a previously defined setpoint.
Display =
OVEN MAXIMUM
as 350
In this case, an oven temperature greater then 350°C was attempted while the OVEN MAX is
set to 350°C.
Setting Heated Zone Temperatures 3-5
Using Cryogenic Oven Cooling
Oven temperature may be controlled below ambient when a cryogenic valve is present.
Cryogenic control setpoints are:
CRYO ON
To enable subambient control of the oven
CRYO OFF
To disable subambient cooling of the oven; the
default state for the cryogenic valve is OFF.
CRYO BLAST ON
To enable very fast cool-down time after a run
CRYO BLAST OFF
To disable very fast cooling of the oven
AMBIENT
Sets optimal temperature control for efficient use
of cryogenic fluid. (The default temperature
setting is 25 °C.)
CRYO FAULT ON/OFF
A fault occurs when the oven does not reach set
temperature after 17 minutes of continuous cryo
operation. The oven turns off and WARN:0VEN SHUT
OFF is displayed. Turning Cryo Fault OFF will disable
this feature.
CRYO TIMEOUT XXX MIN
A cryo timeout occurs when a run does not start
within a specified time (10 to 120 minutes) after the
oven equilibrates. Turning Cryo Timeout OFF will
disable this feature. Default is ON for 30 minutes.
When on, the cryogenic valve (if installed) operates automatically to obtain an oven temperature when there is demand for coolant to be supplied to the oven.
When cryogenic cooling is NOT needed, cryogenic valve operation MUST be turned off. If
this is not done, proper oven temperature control may not be possible, particularly at temperatures near ambient.
The Cryo Blast feature can operate together with or independently of Cryo On/Off. Cryo Blast
cools the oven faster AFTER a run than it normally would under normal cryogenic operation.
This allows the HP 5890 to become ready for the next run earlier than it would without cryo
blast on. This feature is useful when maximum sample throughput is necessary.
Setting Heated Zone Temperatures 3-6
Successively pressing the I CRYO PARAM 1 key scrolls through functions related to cryogenic
valve operation. To turn cryogenic operation on/off and cryogenic blast on/off, the following
key sequence is used:
ON I or [OFF
[
CRYO PARAM
^
[ ON
To turn Cryo Blast operation on or off, the following key sequence is used:
ON
[
CRYO PARAM
1
SCROLL TO CRYO BLAST
I or
[OFF
f~ON~
An example key sequence to change the ambient temperature setting to 23 °C is:
ElSSiEia
C CRYO PARAM 1
SCROLL TO AMBIENT I 2 I I 3 1 [ ENTER j
Ambient temperature is setable to allow fine tuning of cryogenic operation. The default setting
is 25 °C and for most applications need not be changed. For more information about adjusting
the ambient cryogenic setting, see the HP 5890 SERIES II Reference Manual.
The following figure shows displays associated with disabling/enabling automatic cryogenic
valve operation.
Displays, Cryogenic Valve Operation
ACTUAL
SETPOINT
mmmmmmmmmmimmmmmmmmm
ACTUAL
SETPOINT
mmmmmmmmm® wmmmmmmm
ACTUAL
SETPOINT
CRYO FAULT ON
ACTUAL
SETPOINT
CfiYO TIMEOUT 20 Mitt
Setting Heated Zone Temperatures 3-7
Programming Oven Temperatures
The oven temperature may be programmed from an initial temperature to a final temperature
(in any combination of heating or cooling) using up to three ramps during a run.
Oven temperature programming keys include:
INXT VALUE
INJT TIME
RATE
The starting temperature of a temperature programmed run. This is also the temperature the oven
returns to at the end of a temperature programmed
run.
The length of time the oven will stay at the starting
temperature after a programmed run has begun.
Controls the rate at which the oven will be heated or
cooled in degrees C/min. A temperature-programming rate ofO halts further programming.
FINAL VALUE
Temperature the oven will reach at the end of a
heating or cooling temperature-programmed run.
FINAL TIME
The length of time the oven temperature will be
held at the final temperature of a temperatureprogrammed run.
Total elapsed time for a run cannot exceed 650 minutes. At 650 minutes, the run terminates
and oven temperature returns to the initial oven temperature. In isothermal operation
(RATE = 0), the instrument internally sets run time to the maximum of 650 minutes.
Setting Heated Zone Temperatures 3-8
Examples
A Single-Ramp Temperature Program: Programming oven temperature from 100°C to 200°C
at 10°C/min.
Current oven temp = 100°C, Display =
OVEN TEMP
100
100
Example setpoints for a single-ramp temperature program:
INIT VALUE
INIT TIME
RATE
FINAL VALUE
FINAL TIME
100
2
10
200
1
Single-Ramp Temperature Program
FINAL
VALUE
\ Cool-down
\ (Uncontrolled)
INIT
VALUE
EQUIB
ILM£ _
INIT
TIME
Oven Ready
for Next Run
Time
Run Terminates
Automatically
Setting Heated Zone Temperatures 3-9
A TVvo-Ramp Temperature Program: Oven temperature will be held at 100 °C for 2 minutes,
then program from 100pC to 200°C at 10°C/min for the first ramp.
Oven temperature will be held at 200 °C for 2 minutes, then program from 200 °C to 250 °C at
5°C/min for the second ramp.
Example setpoints for a two ramp oven program:
1ST RAMP
2ND RAMP
INIT VALUE
INIT TIME
RATE
FINAL VALUE
FINAL TIME
100
2
10
200
2
RATE A
FINAL VALUE
FINAL TIME
5
250
1
Two-Ramp Temperature Program
FINAL
VALUE A
RATE A
FINAL
VALUE
RATE
FINAL \
Time A »
Cool-down
(uncontrolled)
FINAL
TIME
EQU1B
TIME oven Ready
for Next Run
INIT
VALUE
INIT
TIME
Run Time
Run Terminates
Automatically
Setting Heated Zone Temperatures 3-10
A Three-Ramp Temperature Program: Oven temperature will be held at 100°C for 1 minute,
then program from 100°C to 200°C at 10°C/min for the first ramp.
Oven temperature will be held at 200°C for 2 minutes, then program from 200 °C to 250°C at
10°C/min for the second ramp.
Oven temperature will be held at 250°C for 2 minutes, then program from 250 °C to 300° C at
10°C/min for the third ramp. Oven temperature will be held at 300°C for 1 minute before
returning to the initial starting temperature of 100°C.
Example setpoints for a three-ramp oven program:
1ST RAMP
INIT VALUE
INIIT TIME
RATE
FINAL VALUE
FINAL TIME
100
1
10
200
2
2ND RAMP
RATE A
FINAL VALUE
FINAL TIME
3RD RAMP
RATE B
FINAL VALUE
FINAL TIME
10
250
2
10
300
1
Three-Ramp Temperature Program
FINAL
VALUE B,
Cool-down
t (uncontrolled)
EQUIB
INIT
VALUE
INIT
TIME
Oven Ready
for Next Run
Run Time
Run Terminates
Automatically
Setting Heated Zone Temperatures 3-11
A Three-Ramp Temperature Program (with a controlled cool-down step): Oven temperature
will be held at 100°C for 1 minute, then program from 100°C to 200°C at 10°C/min for the
first ramp.
Oven temperature will be held at 200 °C for 2 minutes, then cool (controlled) from 200 °C to
150°C for the second ramp.
Oven temperature will be held at 150° C for 1 minute, then program from 150° C to 250° C at
10°C/min for the third ramp. Oven temperature will be held at 250°C for 2 minutes before
returning to the initial starting temperature of 100° C.
Example setpoint conditions for a three-ramp oven program:
1ST RAMP
INiT VALUE
INITTIME
RATE
FINAL VALUE
FINAL TIME
2ND RAMP
3RD RAMP
100
1
RATE A
FINAL VALUE
FINAL TIME
10
200
2
5
150
1
RATE B
FINAL VALUE
FINAL TIME
10
250
2
Three-Ramp Temperature Program with a Cooling Step
FINAL
VALUE B
Cool-down
(controlled)
FINAL
VALUE
RATEB
FINAL
TIME
RATE
\d
YRATEA
FINAL
INIT
TIME
I
I
Cool-down
(uncontrolled)
\
VALUEA
FiNAT
TIME A
INIT
VALUE
FINAL \
TIME B
EQUIB
Oven Ready
for Next Run
Run Time
Run Terminates
Automatically
Setting Heated Zone Temperatures 3-12
Setting Inlet and Detector Temperatures
Inlet and detector temperatures may be controlled anywhere from room temperature to 400° C.
Inlet and detector temperature control keys include:
INJ A TEMP
To set temperature for the inlet in the A position
INJ B TEMP
To set temperature for the inlet in the B position
DET A TEMP
To set temperature for the detector in the A position
DET B TEMP
To set temperature for the detector in the B position
Displaying Inlet and Detector Temperature
Press [
INJ A TEMP
1 (or [
INJBTEMP
I ) to display the current inlet temperature.
100
Sample Display =
100
Press [ PET A TEMP I (Or [ DET B TEMP 1 ) to display the current detector temperature.
Sample Display =
100
DET A VEWP
100
An inlet or detector is switched on or off with key sequences:
[
INJ A TEMP J
or [
INJ B TEMP
( [_ DET A TEMP J o r I DET B TEMP J
ON \ j [OFF
\ [ ON \ j [OFF \
The inlet or detector is also switched on by entering a new setpoint value; the new value
replaces OFF or the previous value.
Setting Heated Zone Temperatures 3-13
Example
Setting Inlet Temperature to 200 C
Current inlet temp = OFF
Display =
Press:
(t
INJATEMPI
or [
|N4 A TEMP
INJBTEMP
38
1 ) 12 I I o I 1o 1 (
OFF
ENTER
The inlet temperature will change from OFF to 200°C and stabilize.
Setting Detector Temperature to 200 C
Current detector temp = OFF
Display =
Press:
(I
DETATEMP
1 or [
BET A TEMP
PETBTEMP
1 ) 12 1 10 I 10 I
38
[ENTER
OFF
1
The detector temperature will change from OFF to 200°C and stabilize.
Setting Heated Zone Temperatures 3-14
Setting Auxiliary Temperatures
AUX TEMP
AUX TEMP is usually used for heated valve compartment,
heated transfer line, etc.
INJ A TEMP
INJ B TEMP
Any of these keys may control an auxiliary heated zone
depending upon the instrument configuration.
DET A TEMP
DET B TEMP
Instructions are provided in a separate envelope when a temperature control key has been
assigned to a heated zone other than the zone it identifies.
As an example, to set the AUX TEMP heated zone to 100° C,
Press• EMJI1 [ AUX TEMP 1 I 1 I I 0 1 [ 0 \ I ENTER I
Setting Heated Zone Temperatures 3-15
Instrument Rear
Heated Zone Temperature Control
Key Assignments
INJA
TEMP
AUX
TEMP
3ys
Any of the keys
DETB
TEMP
DETA
TEMP
INJB
TEMP
, depending upon
which zones are unused.
Inlet Zone
INJB
TEMP
B
Valve Zone
Detector Zone
Valve Box
INJA
TEMP
Setting Heated Zone Temperatures 3-16
B
DETB
TEMP
DETA
TEMP
Contents
Chapter 4:
Setting Inlet System Flow Rates
Measuring Row Rates
Using a Bubble Flow Meter
Required Adapters for Measuring Row Rates
Changing the Packed Inlet Flow Ranges
Changing the Source Pressure
Setting the Packed Inlet Flow with Septum Purge
Manual Flow Control:
Electronic Pressure Control:
Setting the Split/Splitless Capillary Inlet Flow
Setting the Split Mode Row
Manual Row Control:
Electronic Pressure Control:
Setting the Splitless Mode Row
Manual Row Control:
Electronic Pressure Control:
Manual Purge Switching:
Automatic Purge Switching:
Displaying the Gas Row Rate
Designating Gas Type
Using the Internal Stopwatch
4-1
4-2
4-4
4-5
4-5
4-6
4-6
4-7
4-9
4-11
4-11
4-12
4-18
4-18
4-19
4-21
4-21
4-25
4-25
4-27
4
Setting Inlet System Flow Rates
This chapter provides operating information for the following HP 5890 inlet systems:
• Septum-purged packed column inlet
• Split/splitless capillary inlet
Operating information for the Programmable Cool On-Column Inlet is provided in a separate
manual included with the HP 5890.
Measuring Flow Rates
Use a bubble flow meter to initialize all flows for the first time and to check them whenever the
system is changed in some way.
Bubble Flow Meter for Measuring Flow Rates
Setting Inlet System Flow Rates
4-1
Using a Bubble Flow Meter
A bubble flow meter with rate ranges of 1, 10, and 100 ml/min is suitable for measuring both
low flow rates (such as carrier gases) and higher flow rates (such as air for an FID).
A bubble flow meter is a very basic, reliable tool for measuring gas flow. It creates a bubble
meniscus across a tube through which the gas is flowing. The meniscus acts as a barrier and its
motion reflects the speed of the gas through the tube. Most bubble flow meters have sections of
different diameters so they can measure a wide range of flows conveniently.
1. Attach one end of the bubble flow meter adapter to the flexible gas-inlet line of the bubble
flow meter.
2. Attach the other end of the adapter to the detector outlet exhaust vent or other vent
through which you will measure flow.
3. Fill the bulb of the bubble flow meter with soapy water or leak detection fluid (such as
Snoop®).
4. Prepare the built-in stopwatch on the keyboard using the following keystrokes on its keypad:
Press: t
TIME
1 up to three times.
The display on the oven module now displays zeroes for the time (t) and the reciprocal time
5. While holding the bubble flow meter vertically, squeeze and release the bulb to create a
meniscus in the bubble flow meter.
6. Press: [ ENTER 1 to start the stopwatch when the meniscus passes the lowest line in the
bubble flow meter.
7. Press: [ ENTER 1 to stop the stopwatch when the meniscus passes the upper line in one of the
tube sections.
Setting Inlet System Flow Rates
4-2
8. Calculate the flow rate in ml/min:
•
If you stopped the meniscus at the first line, the flow rate is numerically equivalent to
the reciprocal time reading displayed on the oven module.
•
If you stopped the meniscus at the second line, the flow rate is numerically equivalent to
10 times the reciprocal time reading displayed on the oven module.
•
If you stopped the meniscus at the third line, the flow rate is numerically equivalent to
100 times the reciprocal time reading displayed on the oven module.
9. Press: 1 CLEAR 1 and repeat steps 5 through 8 at least once to verify the flow.
10. Start the makeup gas flow by turning the Aux Gas knob on the upper-left portion of the
oven front counterclockwise until the valve is in the open position.
11. Measure the total gas flow by repeating steps 5 through 8.
12. If the flow is not correct:
• Wait at least 2 minutes for the flow through the system to stabilize.
• Repeat the above procedure as necessary.
Note: If you use an FID, TCD, or NPD, use a small screwdriver to adjust the variable
restrictor at the center of the Aux Gas knob as necessary.
Setting Inlet System Flow Rates
4-3
Required Adapters for Measuring Flow Rates
In general, inlet system, or column, flow rates are measured at detector exhaust vents. Septum
purge and split flow rates for capillary inlet systems are measured at vents located on the front
of the flow panel. A rubber adapter tube attaches directly to an NPD, ECD, or TCD exhaust
vent tube.
A special flow-measuring adapter is supplied for an FID. Attach a bubble flow meter to the
FID flow-measuring adapter and insert it into the detector exhaust vent as far as possible. You
may feel initial resistance as the adapter's O-ring is forced into the detector exhaust vent. Twist
and push the adapter during insertion to ensure that the O-ring forms a good seal.
WARNING
TO MINIMIZE THE RISK OF EXPLOSION, NEVER MEASURE AIR AND H 2
TOGETHER. MEASURE THEM SEPARATELY.
Required Adapters for Measuring Gas Flow Rates
FID Use
NPD, TCD, and ECD Use
Setting Inlet System Flow Rates 4-4
Changing the Packed Inlet Flow Ranges
You may want to change the flow range of your inlet for a number of reasons. For example, if
you are using flows in the lowest 20 percent of a flow restrictor's range, the retention times of
your analysis might wander. By changing from a flow of 20 ml/min with a flow restriction range
of 0 to 110 ml/min to one with a range of 0 to 20 ml/min, you can eliminate this problem.
You can change the flow ranges in packed inlets by either:
• Changing the source pressure, or
• Changing the flow restrictor in the flow controller. For instructions on changing the flow
restrictor, turn to page 2-7 of the Site Prep/Installation Manual.
Changing the Source Pressure
You can increase the upper limit of flow from a flow controller by increasing the source
pressure. The following table lists the maximum flows for the standard flow controller for a
packed inlet with a 0 to 20 ml/min flow restrictor at five pressures. For maximum H2 flows, read
from the Helium Flow column.
Source Pressure (Dsi)
Nitroaen Flow (ml/min)
Helium Flow (ml/min)
40
50
60
70
80
20
24
28
32
36
21
25
28
32
35
Setting Inlet System Flow Rates 4-5
Setting the Packed Inlet Flow with Septum Purge
Use the following steps to set the packed inlet flow:
1. Set the oven and heated zone temperatures to the desired operating values.
Note: Never heat the column until the flow rates are set.
2. Turn off the detector (particularly an NPD or TCD), if it is not off already, until you set the
carrier flow rate.
Note: The detector signal can be assigned to an appropriate output channel.
3. Set the carrier source pressure to at least 275 kPa (40 psi) to ensure proper operation for
most applications.
Note: Carrier source pressure must be at least 105 kPa (15 psi) greater than the maximum
column head pressure.
4. Turn off any other support gases to the detector (such as H2, air, reference flow, or capillary
makeup gas) to permit independent measurement of column flow rate.
5. Your inlet is equipped with either manual or electronic flow control. Set the column head
pressure according to the appropriate section below.
Manual Flow Control:
Turn the mass flow controller counterclockwise as necessary to obtain the desired flow rate,
as measured with a bubble flow meter at the detector exhaust vent.
Setting Inlet System Flow Rates
4-6
Electronic Pressure Control:
a. Select the pressure units you would like to use.
To change the units, press: $*$$&& I 1 1 [ ENTER 1. Then press the number of the
corresponding unit you want to use:
G D = kPa
b. The example below sets Inlet B (Injector B) pressure to 10 psi. Use the example to set
the pressure you have selected.
c. Press:
l
[
INJBPRES J
ACTUAL
EPP B
10.0
( i
ENTER |
Sets inlet B pressure to 10 psi.
SETPOINT
10.0
The GC display looks like this
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control."
6. Check the septum purge flow rate:
The septum purge flow is fixed. Although it is not adjustable, you should check the flow. Do
not cap off the flow from the purge vent.
Carrier Gas Type
Approx. Flow
H2
He
N2
Argon/Methane
1.2-2.2 ml/min
1.0-1.8
0.6-1.2
0.5-1.1
7. Recheck the column flow rate and adjust as necessary.
Setting Inlet System Flow Rates
4-7
Flow Panels Controlling Purged Packed Inlet
Manual Pressure Control
Pressure
Gauge
Mass Flow
Controller
Septum
Purge
Vent
Electronic Pressure Control
PURGED PACKED
PROGRAMMABLE PRESSURE
Septum
Purge
Vent
Setting Inlet System Flow Rates
4-8
Setting the Split/Splitless Capillary Inlet Flow
Set the linear velocity through the column when using capillary columns. Linear velocity is
controlled by pressure at the head of the column. Pressure required to obtain a particular
velocity depends primarily upon the bore (id) of the column, length of the column, and oven
temperature.
Hewlett-Packard fused-silica capillary columns are categorized according to their bores. The
table below lists the initial pressures for some capillary column bores and lengths.
The high pressure in each range is recommended as a starting point for most analyses and
yields a good compromise between efficiency and speed of analysis. The following sections
provide procedures to adjust head pressure to obtain any desired flow velocity through the
column.
Suggested Initial Head Pressures 1or Capillary Columns
Column
id (mm)
Column
Length (m )
Helium (Harrier Gas
Hydrogen Carrier Gas
psi
psi
kPa
0.20
0.20
0.20
12
25
50
85 - 140
145 - 235
235 - 360
0.32
0.32
0.32
12
25
50
29 - 53
55 - 95
95 - 160
0.53
0.53
10
30
8.524. 0 -
16
44
12
21
34
-
kPa
21
34
52
4.27.914.0-
7.7
14
23
1.23.5-
2.4
6.3
48 - 84
87 - 145
145 - 230
7
13
21
-
1?
21
34
17 - 32
33 - 60
60 - 105
2.54.88.7-
4.7
8.7
15
5.0 14.0 -
0.72.1 -
1.4
3.9
9.7
27
When using the 5-m x 0.53-mm id checkout column, the suggested pressure is 15 kPa (2.2 psi)
with He gas flow of 20 ml/min.
Setting Inlet System Flow Rates
4-9
Flow Panels Controlling Split/Splitless Inlet
Manual Pressure Control
Pressure
Gauge
Column Head.
Pressure
Control
Total Flow
Controller
. Septum
Purge
Vent
Split Vent
Electronic Pressure Control
Total Flow
Controller
Septum
Purge
Vent
Split Vent
Setting Inlet System Flow Rates
4-10
Setting the Split Mode Flow
WARNING
WHEN PERFORMING SPLIT SAMPLING AND USING HAZARDOUS CHEMICALS
AND/OR H 2 CARRIER GAS, VENT EFFLUENT FROM THE SPLIT VENT AND SEPTUM
PURGE VENT TO A FUME HOOD OR APPROPRIATE CHEMICAL TRAP.
To ensure proper operation, make sure the carrier source pressure is at least 105 kPa (15 psi)
greater than the selected column head pressure.
1. Use the following steps to set the initial column head pressure:
a. Set the column head pressure to 0:
Press:
b. Increase the total flow control as necessary to obtain 100 ml/min measured at the split
vent.
c. Increase the column head pressure to obtain the selected pressure.
Your inlet is equipped with either manual or electronic pressure control. Set the column
head pressure according to the appropriate instructions below.
d. Set the oven and heated zone temperatures to the desired operating values. Make sure
the detector is turned on and its output signal is assigned to an appropriate channel (see
Chapter 6, "Controlling the Signal Output").
Manual Flow Control:
Turn the mass flow controller counterclockwise to establish flow. This will cause the
gauge pressure to increase.
Setting Inlet System Flow Rates
4-11
Electronic Pressure Control:
a. Select the pressure units you would like to use.
l i i l I 1 1 I ENTER I . Then press the number of the
To change the units, press: PiP&Si
corresponding unit you want to use:
b. The example below sets Inlet B (Injector B) pressure to 10 psi. Use the example to
set the pressure you have selected.
c. Press:
Sets inlet B pressure to 10 psi
INJ B PRES
ACTUAL
BPP 8
SETPOINT
10,0
10.0
The GC display looks like this
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control. "
2. Check the septum purge flow rate.
Excess carrier gas is vented through the septum purge vent. Although the septum purge vent
is not adjustable, you should check the flow. Do not cap off the flow from the purge vent.
Carrier Gas Type
Approx. Flow
H2
He
N2
Argon/Methane
3.5-6.0 ml/min
1.5-3.5 ml/min
1.5-3.5 ml/min
1.5-3.5 ml/min
Setting Inlet System Flow Rates
4-12
3. Set the linear velocity:
Using the timer feature (see "Using the Internal Stopwatch" in this chapter) and repeated
injection of an unretained component, adjust the column head pressure as necessary to
obtain the expected retention time for the desired linear velocity.
Linear velocity through the column is measured by injecting a sample containing an
unretained component (typically CH4 or air).
The observed retention time for the unretained component is compared to an expected
retention time (tr) calculated from the desired linear flow velocity (\i) and the length of the
column:
Column Length (m)
tr (expected) (in min) = 1-67 -—
Linear Flow Velocity (cm/sec)
4. Calculate the volumetric flow rate, if desired:
Use the following formula to simplify the calculation of volumetric flow through a capillary
column:
Volumetric Flow Rate (cm3/min) = 0.785
where D is column internal diameter
L is column length
tr is retention time (min) of an unretained component, assuming the
desired linear velocity (|i) has been obtained
This calculation becomes less accurate as pressure and gas compression are increased.
Setting Inlet System Flow Rates
4-13
The table below lists values of 0.785 x D2L for capillary column bores and lengths:
Values of 0.785 x D2L for Various Capillary Column Bores and Lengths
Nominal
id (mm)
Nominal Length (m)
12
25
50
0.20
0.377
0.785
1.57
0.25
0.589
1.22
2.45
0.32
0.965
2.01
4.02
0.53
2.65
5.51
11.0
0.75
5.30
11.0
22.1
5. Use a bubble flow meter connected at the detector exhaust vent to verify the calculated
volumetric flow rate through the column. (For bubble flow meter operating instructions, see
"Using a Bubble Flow Meter" earlier in this chapter.) Turn off any other gases to the
detector, such as makeup and/or support gases.
6. Use the following steps to verify that the inlet split flow is currently passing through the inlet
insert and will remain so throughout runs that are made in split sampling mode:
a. Display the current inlet split vent status:
Press:
C PURGE/VALVE ^
[ A \
(or I
B
1) .
If OFF is displayed, press: 10N 1 to restore split flow through the inlet insert.
b. Display the time at which the split flow will be halted:
Press: I
PURGE/VALVE ^
[ A\
(Or I
B
\ ) i TIME I (OFF
c. Display the time at which the split flow will be restored:
Press: I
PURGE/VALVE ^
(or just press: ION 1 if
[ A 1 (or I
VALVE TIME
Setting Inlet System Flow Rates 4-14
B
1) ( TIME I | ON \ g
is already displayed).
d. Alternatively, set both times to 0.00 and turn on Purge A (or B):
Press: t ° ) [ ENTER 1 when the GC display reads:
ACTUAL
SETPOINT
PURGE VALVE A TIME ON
7. Use the following steps to obtain the desired split ratio:
a. Measure the flow rate at the split vent using a bubble flow meter. For bubble flow meter
operating instructions, see "Using a Bubble Flow Meter" in this chapter.
b. Adjust the total flow control as necessary to obtain the flow rate required for the desired
split ratio.
c. Choose the split ratio appropriate for the analysis.
From the definition for the split ratio, use the following relationship to determine the
flow rate to be expected at the split vent for any desired split ratio:
Split Vent Flow Rate (ml/min) =
Volumetric Column Flow Rate (ml/min) x (Desired Split Ratio - 1)
Setting Inlet System Flow Rates
4-15
Split Flow Diagram for Electronic Pressure Control
Total Flow
Control
104 ml/mln
Capillary Inlet
3 mffmin Septum Purge Row
Fixed Restrictor Purge Vent
for Septum Purge ^ ^ ^ ^
3 ml/min
'100 ml/min
100 ml/min Split Flow
• % Split Vent
Inlet Purge
Control Valve
ACTUAL
EPP B
10,0
SETPOINT
10,0
Electronic Pressure
Controlled through
Keyboard Entry
To Detector
1 ml/min
Column Flow
This example shows a 100:1 split ratio
100 ml/min Split Flow
1 ml/min Column Flow
Setting Inlet System Flow Rates
4-16
Split Flow Diagram for Manual Pressure Control
Total Flow
Control
Septum Purge
Control
Capillary Inlet
15
Septum Purge
Vent
3 ml/min
3 ml/min Septum Purge Flow
100 ml/min
too mj/min Split Row
Split Vent
Purge Control Valve
Column Head
Pressure
Control
To Detector
1 ml/min
Column Flow
This example shows a 100:1 split ratio
100 ml/min Split Flow
1 ml/min Column Flow
Setting Inlet System Flow Rates
4-17
Setting the Splitless Mode Flow
WARNING
WHEN PERFORMING SPLITLESS SAMPLING AND USING HAZARDOUS
CHEMICALS AND/OR H 2 CARRIER GAS, VENT EFFLUENT FROM THE SPLIT
VENT AND SEPTUM PURGE VENT TO A FUME HOOD OR APPROPRIATE
CHEMICAL TRAP.
To ensure proper operation, make sure the carrier source pressure is at least 105 kPa (15 psi)
greater than the selected column head pressure.
Use these steps to set the splitless mode flow. This procedure assumes that detector gases are
connected, the system is leak-free, and the column and insert are properly installed.
1. Use the following steps to set the initial column head pressure:
a. Set the column head pressure and total flow controls to 0.
Press:
E&iM$
L INJAPRES 1
(Or [
INJ B PRES 1 ) 1 o 1 [ ENTER 1
Sets
the
EPC
/ n / e t e to
0
b. Increase the total flow control as necessary to obtain 50 ml/min measured at the inlet
vent.
c. Increase the column head pressure to obtain the selected pressure.
Your inlet is equipped with either manual or electronic pressure control. Set the column
head pressure according to the following instructions for your inlet.
d. Set the oven and heated zone temperatures to the desired operating values. Make sure
the detector is turned on and its output signal is assigned to an appropriate channel (see
Chapter 6, "Controlling Signal Output").
Manual Flow Control:
Turn the mass flow controller counterclockwise to establish flow. This will cause the
gauge pressure to increase.
Setting Inlet System Flow Rates
4-18
Electronic Pressure Control:
a. To change the units, press: iiiiiS^Silil t i I [ ENTER \ . Then press the number of the
corresponding unit you want to use:
Hri = psi
[~5~1 = kPa
b. The example below sets Inlet B (Injector B) pressure to 10 psi. Use the example to
set the pressure you have selected.
c. Press:
m
[
INJ B PRES J
[
ACTUAL
BPP B
ENTER 1
1
10,0
Sets inlet B pressure to 10 psi
SETPOINT
10,0
The GC display looks like this
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control. "
2. Check the septum purge flow rate if you have an EPC system.
Excess carrier gas is vented through the septum purge vent. Although the septum purge vent
is not adjustable, you should check the flow. Do not cap off the flow from the purge vent.
Carrier Gas Type
Approx. Flow
H2
He
N2
Argon/Methane
3.5-6.0 ml/min
1.5-3.5 ml/min
1.5-3.5 ml/min
1.5-3.5 ml/min
Setting Inlet System Flow Rates 4-19
3. Set the linear velocity:
Use the timer feature (see "Using the Internal Stopwatch" in this chapter) and make
repeated injections of an unretained component. Then adjust the column head pressure as
necessary to obtain the expected retention time for the desired linear velocity.
Linear velocity through the column is measured by injecting a sample containing an
unretained component (typically CH4 or air).
The observed retention time for the unretained component is compared to an expected
retention time (tr) calculated from the desired linear flow velocity (\i) and the length of the
column:
V(expected) 0 n m i n ) = I - 6 7
Column Length (m)
Linear Flow Velocity (cm/sec)
4. Use the following steps to set the splitless injection timetable:
Splitless injection is made possible by redirecting the inlet purge flow away from the inlet
insert at the time of injection. After injection, sufficient time is allowed for solvent and
sample components to reconcentrate at the head of the column. Then by redirecting the
purge flow back through the insert, solvent vapor within the inlet insert is purged.
There are two purge control channels, one for inlet A and one for inlet B.
a. To redirect the purge flow away from the column to allow for a splitless injection:
Press:
I
PURGE/VALVE
1
I A | (or [ B | ) [OFF|.
Note: Flow through the insert at this point passes only through the column.
b. To restore the inlet purge flow:
Press:
L
PURGE/VALVE
1
1 A | (or
Setting Inlet System Flow Rates 4-20
Manual Purge Switching:
Use the keyboard to switch the splitless solenoid valve on or off manually. Attempting to
switch the valve on (or off) when it is already on (or off) has no effect.
The figure below shows typical displays for current valve status and for verifying the timed
events table to switch the valve automatically during a run.
Typical Split/Splitless Inlet Purge Displays
ACTUAL
INL
PURGE
A
ON
INL
PURGE
B
ON
ACTUAL
ACTUAL
PURGE
B
ON
ACTUAL
PURGE
B
OFF
SETPOINT
SETPOINT
SETPOINT
1.50
SETPOINT
0.10
Automatic Purge Switching:
Use the steps below to switch the splitless solenoid valve on or off automatically once during
a run. The valve remains in its final state after termination of the run.
a. To put the inlet into the splitless mode:
Press:
C PURGE/VALVE
^
[ A
b. Set the on time value.
The on time value is the specific time delay after injection for the insert purging to
occur. The on time value depends upon the components, solvent, injection volume, flow
rate through the inlet, and internal insert volume (approximately 1 ml). Generally, an on
time value between 0.6 and 1.5 minutes is reasonable.
Press:
C PURGE/VALVE
(or I
IME 1 1 ON \
o n
time value
1 ENTER 1 .
Setting Inlet System Flow Rates 4-21
c. Set the off time value.
The purge A (or B) off time value should be somewhat less than the total length of the
time for the run. Inlet purge flow is switched off automatically just prior to the end of
the run to ensure that the inlet valve is in the correct state for the start of the next run.
Press: [
PURGE/VALVE
1 1 A | (Or I
B
1) i
TIME
1
(OFF|
off time value 1 ENTER 1.
d. To display the time during the run when the purging will be halted:
Press: [
PURGE/VALVE!
I A \ (Or I B \)
e. To display elapsed time during the run when purging will be restored:
Press:
C PURGE/VALVE"
Once the inlet purging event is displayed, you can enter a new elapsed time (to 0.01
minute or similar) at any time. Elapsed time to halt inlet purging must be prior to
injection (typically 0.00). Both on and off times are referenced to the start of the oven
program.
Note: Any entered value from 0.00 through 650.00 minutes is valid. However, the system
ignores an entered time greater than that of the run time itself and does not switch the
purge valve. The system also ignores the switch command if the programmed on and off
times are the same.
For information about EPC (constant pressure, optimizing splitless injection), see
chapter 10, "Using Electronic Pressure Control."
Setting Inlet System Flow Rates
4-22
Splitless Flow Diagram for Electronic Pressure Control
Total Flow
Control
Purge A (or B) ON
Capillary Inlet
Septum Purge
Vent
3 miymin Septum Purge Flow
54 mt/min
50 ml/mm
3 ml/min
Purge Flo
50 ml/min
Split Vent
Purge Control Valve
EPP B
1 ml/mm
54 ml/mln
SETPOINT
10.0
10,0
*
Electronic Pressure
Controlled through
Keyboard Entry
To Detector
Total Flow
Control
ACTUAL
Purge A (or B) OFF
Capillary Inlet
Septum Purge
Vent
53 ml/min
3 ml/min
50 ml/mlfttniet Purge Flow
3 ml/min
a
50 ml/min
vww
Split Vent
Purge Control Valve
EPP B
To Detector
ACTUAL
SETPOINT
10.0
10.0
Electronic Pressure
Controlled through
Keyboard Entry
1 ml/min
Setting Inlet System Flow Rates 4-23
Spliliess Flow Diagram for Manual Flow Control
Total Flow
Control
Purge A (or B) ON
Capillary Inlet
Septum Purge
Control
3 ml/min
3 ml/tain Septum Purge Flow
Purge Fto
50/ml/mfe
50 ml/min
Split Vent
Purge Control Valve
Column Head
Pressure
Control
To Detector
1 ml/min
Total Flow
Control
Purge A (or B) OFF
Capillary Inlet
3 ml/min
53 ml/min
Septum Purge
Control
Septum Purge
Vent
3 ml/min
50 ml/min
5Qffll/mfofotet Purge Flow
Split Vent
Purge Control Valve
To Detector
1 ml/min
Setting Inlet System Flow Rates
4-24
Column Head
Pressure
Control
Displaying the Gas Flow Rate
Note: If you have EPC, you will not have this feature.
If electronic flow sensing (EFS) is installed in the carrier gas system to the inlet, you can display
total supply flow rate through the system. To display the total supply flow rate:
Press: I FLOW I p T j
(or (~B~1 ) .
(EFS cannot be used with EPC inlets.) Typical gas flow rate displays are shown below.
Typical Electronic Flow Rate Sensor Displays
ACTUAL
FtOW A
26.4
ACTUAL
NO
SETPOINT
N* 1
SETPOINT
F t O W SENSOR
Designating Gas Type
To scale the displayed flow rate value properly, you must designate one of the four commonly
used gases. Select the appropriate gas type from the table below.
Defining Type of Gas to Be Monitored
Number
1
2
3
4
Gas Type
Preferred Use
He (Helium)
N 2 (Nitrogen)
H 2 (Hydrogen)
Ar/CH 4 (Methane in Argon)
TCD
General
Capillary
ECD
Setting Inlet System Flow Rates
4-25
Use the steps below to select one of these gases for a particular flow channel.
1. Press: I FLOW 1 f T l
( or p n )
to
display flow A (or B).
2. Press: 1 1 I , I 2 I , I 3 I , or I 4 I followed by I ENTER 1.
The current flow rate is displayed and scaled appropriately for the chosen gas type.
To use a gas other than the four standard gases listed above, select the standard gas (He, N2,
H2, or Ar-Me/CH4) closest in thermal conductivity to the gas being used.
WARNING
DO NOT PASS ANY CORROSIVE GAS THROUGH THE EFS.
The maximum usable range for H2 is 100 ml/min. If flow rates above 100 ml/min are used, a gas
other than He, N2, or AR/CH4 is being used, or maximum accuracy in displayed flow rate is
required, you may need to calibrate the EFS. See the HP 5890 Series II Reference Manual.
Setting Inlet System Flow Rates
4-26
Using the Internal Stopwatch
The stopwatch timer is useful for setting gas flow rates and measuring elapsed time between
events of interest. In stopwatch mode, both time (to 0.1 second) and reciprocal time (to
0.01 min" 1 ) are displayed simultaneously. Use the following steps to access the stopwatch.
1. Press: t
TIME
2. Press: 1
ENTER
1 repeatedly until the stopwatch display appears.
1 to start the stopwatch. Press: t ENTER I again to stop it.
3. Press: [ CLEAR 1 to reset the stopwatch.
Time Display
Stopwatch Mode
ACTUAL
t = 0 :00. 0
1/t
SETPOINT
= 0 .00
Setting Inlet System Flow Rates
4-27
Contents
Chapter 5:
Operating Detector Systems
Displaying Detector Status
Turning a Detector On or Off
Monitoring Detector Output
Operating Detectors Using Electronic Pressure Control
Accessing Auxiliary Channels C through F
Zeroing the Pressure Channel
Setting Constant Pressure
Setting Pressure Ramps
Changing Pressure Ramps
Example of Setting Pressure Ramps
Verifying Pressure Ramps
Setting Capillary Makeup Gas Flow Rate
Exceptions to Makeup Gas Flow
If the Power FailsO
Shutting Down Each Day
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-9
5-10
5-11
5-12
5-12
5-15
5-15
Operating the Flame Ionization Detector (FID)
Setting Up the FID for Operation
Setting the FID Flow for Packed Columns
Setting the FID Flow for Capillary Columns
Setting the Makeup Gas Flow Rate
Turning the FID On and Off
Igniting the FID Flame
5-16
5-17
5-19
5-21
5-26
5-27
5-28
Operating the Thermal Conductivity Detector (TCD)
Setting Up the TCD for Operation
Setting the TCD Flow for Packed Columns
Setting the TCD Flow for Capillary Columns
Setting the TCD Carrier Gas Type
Setting the TCD Sensitivity
Turning the TCD On and Off
Inverting the TCD Polarity
Using Single-Column Compensation (SCC)
Displaying the Column Compensation Status
Initiating a Column Compensation Run
Assigning Column Compensation Data
5-29
5-30
5-30
5-31
5-33
5-34
5-35
5-35
5-36
5-37
5-38
5-40
Operating the Nitrogen-Phosphorus Detector (NPD)
Setting Up the NPD for Operation
Conditioning the NPD Active Element (Bead)
Setting the NPD Active Element (Bead) Power
Setting the NPD Flow for Packed Columns
Setting the NPD Flow for Capillary Columns
Turning the NPD On and Off
Optimizing the Performance of the NPD
Avoiding Contamination
Preserving the Lifetime of the Active Element
5-42
5-43
5-44
5-45
5-47
5-49
5-52
5-53
5-53
5-54
Operating the Electron Capture Detector (ECD)
Requirements for USA Owners
Introduction
General Considerations
Temperature Effects
Gases
Columns and Flow Rates
Background
Setting Up the ECD for Operation
Setting the Carrier/Makeup Gas Selection Switch
Setting the ECD Flow for Packed Columns
Setting the ECD Flow for Capillary Columns
Testing for Contamination
Testing for Leaks
Testing for Radioactive Leaks (the Wipe Test)
5-56
5-57
5-58
5-59
5-59
5-59
5-60
5-60
5-60
5-61
5-62
5-63
5-66
5-67
5-67
Operating the Flame Photometric Detector (FPD)
Setting Up the FPD for Operation
Setting the FPD Flow for Packed Columns
Setting the FPD Row for Capillary Columns
Turning the FPD On and Off
Igniting the FPD Flame
5-68
5-68
5-69
5-71
5-74
5-74
5
Operating Detector Systems
This chapter provides general and specific operating information for the five HP 5890 Series II
and HP 5890 Series II Plus GC detector systems:
• Flame ionization detector (FID)
• Thermal conductivity detector (TCD)
• Nitrogen-phosphorus detector (NPD)
• Electron capture detector (ECD)
• Flame photometric detector (FPD)
Note: The Series 530 \i column supplied with the HP 5890 must be conditioned before use.
This is done by establishing a flow of carrier gas at 30 to 60 ml/min through the column while
the column is heated at 250°C for at least 4 hours. Refer to the HP 5890 Series IIReference
Manual, "Preventive Maintenance."
Operating Detector Systems
5-1
Displaying Detector Status
To turn a detector on or off, or to display the current status, press: 1DET1 t A 1 (or 1 B 1)
Pressing IDET1 I A 1 (or 1 B 1) while using a TCD toggles the polarity between positive
and negative.
The following occurs when each detector is turned off:
FID: The output signal and collector voltage are switched off. The flame, if already lit,
remains so until gas supplies are turned off.
NPD: The output signal, its collector voltage, and the current through its active element are
switched off.
ECD: The output signal is switched off.
TCD: The output signal, flow modulator valve, and filament current are switched off.
FPD: The output signal and high voltage are switched off. The flame remains lit until gas
supplies are turned off.
Typical Detector Status Displays
DETA
DETA
FID
Operating Detector Systems 5-2
SETPOINT
ACTUAL
SETPOINT
ACTUAL
SETPOINT
ON
TCD
DETB-
ACTUAL
OFF
NOT
INSTALLED
Turning a Detector On or Off
The TCD filament can be permanently damaged if gas flow through the
detector is off or interrupted while the detector is on. Make sure the
detector is off whenever changes/adjustments are made affecting gas
flows through the detector.
Once the desired detector is displayed, press 1 0N ) to turn it on and IOFF ) to turn it off. The
change is immediately displayed.
Note that turning a detector off or on does not affect its zone temperature. Detector temperature is controlled separately through the temperature control key associated with the particular
heated zone ([ DETATEMP~~1 Or [ DETBTCMP~~1 ). For more information, see chapter 3, "Setting
Heated Zone Temperatures."
Operating Detector Systems
5-3
Monitoring Detector Output
Knowing the detector output is particularly useful when you initialize the detector for
operation, for example, when you light the flame for an FID, set the power to an NPD active
element, or check noise (baseline frequency) for an ECD.
1. To display the detector output at any time, assign an output channel (signal 1 and/or
signal 2 if installed) to a particular detector (identified by its location, A or B).
Press: 1 S'Q 1 1 ( or I SIG2 1) 1 A | ( Or 1 B I) 1 ENTER 1 m
2. Display the signal level for the detector by pressing I SIG1 i (or I SIG2 1).
3. Press: [ SIGI 1 (or I SIG2 1) again to display the signal source assigned to the particular
output channel.
The figure below shows typical displays:
Typical Displays for Monitoring the Detector Output Signal
SIGNAL 1
ACTUAL
SETPOINT
ACTUAL
SETPOINT
ACTUAL
SETPOINT
A
SIGNAL 1
0ETA
HOT
INSTALLED
When detector A or B is not installed, signal 1 or 2 will be undefined. If you try to set a
detector that is not installed, the display shows that it is not installed.
The display shows the signal in real time, reacting immediately to anything affecting detector
response. This provides a convenient method for monitoring detector output.
Operating Detector Systems
5-4
Operating Detectors Using Electronic Pressure Control
This section describes general operations for detectors with EPC. The next section describes
how to set flows for systems controlled manually or electronically.
Electronic pressure control allows you to control all auxiliary gases that are configured using
EPC from the keyboard of the HP 5890 GC. Electronic control is available on channels C
through F for auxiliary gases. The figure below shows the HP 5890 GC keyboard, including the
EPC keys that allow you to access channels C through F:
START
OVEN
TEMP
AUXE
PRES
TCD
SENS
AUXF
PRES
DET
I
I
CD
m m m
m m m
CD CD
Channels C through F
Operating Detector Systems
5-5
This section contains basic operating instructions for channels C through F, including:
• Accessing the auxiliary channels
• Zeroing the pressure channel for calibration
• Setting a constant pressure program
• Setting pressure ramps
• Changing pressure ramps
• Verifying pressure ramps
Accessing Auxiliary Channels C through F
The four EPC auxiliary channels are accessed through the existing GC keyboard by using the
following keys:
Press:
To Access:
Auxiliary EPC channel C
Auxiliary EPC channel D
Auxiliary EPC channel E
Auxiliary EPC channel F
After accessing each channel, the GC display shows the channel you have selected and the
actual and setpoint values. For example, after accessing auxiliary EPC channel C, the GC
display might look like this:
EPP C
ACTUAL
SETPOINT
10,0
10.0
Operating Detector Systems
5-6
Zeroing the Pressure Channel
When you zero the pressure, you are compensating for background pressure. The system is
zeroed when it is shipped, but you should check it periodically, especially when the ambient
laboratory temperature changes dramatically.
Note: You should zero the EPC channels 30 to 60 minutes after the system has heated up,
because changes in temperature may cause fluctuations while the instrument heats to its final
temperature.
To zero the channel accurately, all flow must be removed from the system before you enter the
offset value. For each channel, you will first set the channel to zero, and then enter the value
labeled "actual" as the offset. The following example zeroes channel C.
1. Turn off all inlet and detector gases.
2. Depressurize the inlet and detector gases to 0.0 psi.
3. Set the auxiliary EPC channel C pressure to zero:
ACTUAL
EPP C
5,0
The GC display looks like this.
4. Press:
where value is the zero offset value shown on the GC display labeled "actual."
ACTUAL
8PP C
SETPOINT
5,0
5.0
The GC display looks like this.
Follow the same procedure to zero the remaining auxiliary EPC channels. Remember that
the system must be completely depressurized before entering the value labeled "actual."
5. To zero channel D:
a. Press:
b. Press:
Set auxiliary channel D pressure to 0.0.
5 1 1 ENTER 1
ACTUAL
EPP D
5.0
value
I ENTER
SETPOINT
5JQ
The GC display looks like this.
Operating Detector Systems
5-7
6. To zero channel E:
a. Press:
{8&83I&1 [ COLCOMPI~1 I o 1 1
b. Press:
H m
l~6~l
[ ENTER 1
ACTUAL
va[ue
I 1 o I I ENTER 1 Set auxiliary channel E pressure to 0.0.
[ ENTER 1
SETPOINT
£
The GC display looks like this.
7. To zero channel F:
a. Press: — I
[
1 (~o
COLCOMP2
b. Press: Ei&°&i$ f jlJ!
{ ENTER 1
ACTUAL
[
value
1
o_J [ ENTER I
set auxiliary channel F pressure to 0.0.
fENTE?! .
SETPOINT
5.0
$•0
The GC display looks like this.
Setting Constant Pressure
To set constant pressure for each of the four auxiliary channels, (where value is the desired
constant pressure value):
Press:
A|
value t ENTER 1 for EPC channel C.
Press:
ID
value i ENTER 1 for EPC channel D.
Press:
[ COLCOMP1 1
value
Press:
[ CQLCOMP2 1
value I ENTER 1 for E P C channel F.
I ENTER I for E P C channel E.
Note: To enter a constant pressure for a run, the initial time in the program must be as long as
(or longer than) the run time.
After setting the constant pressure for each channel, the GC display shows the channel
you have selected and the actual and setpoint pressure values. For example, if you set EPC
channel C to 60, the GC display looks like this:
ACTUAL
c
SETPOINT
60-0
Operating Detector Systems
5-8
Setting Pressure Ramps
To set pressure ramps for each of the four auxiliary channels (where value is the setpoint value
for the specific part of the ramp):
To set the program for EPC channel C:
mmm
Press: tmmM
RATE |
1 A |
value
[
INIT VALUE
[ ENTER )
1
value
i ENTER 1 [
[ FINAL VALUE
Value
INITTIME
[ ENTER I
[
I
Value
FINAL TIME
I ENTER
1
value
t ENTER 1 .
To set the program for EPC channel D:
Press:
[ia&aijj
[ RATE )
| B |
value
[
INITVALUE~1
[ ENTER )
value
I ENTER 1 [
[ FINAL VALUE j
INITTIME
1
value
value
[ ENTER )
[
FINAL TIME
J
value
[ ENTER )
[
INITTIME
[ FINAL VALUE 1
value
t ENTER 1 [
t ENTER I
J
value
[ ENTER
value
[ ENTER
FINAL TIME
1
value
[ ENTER
INITTIME
J
value [ ENTER
To set the program for EPC channel E:
Press:
["gatd""])
C COLCOMPI
t RATE 1 value
1
( ENTER \
[
INITVALUE
To set the program for EPC channel F:
Press:
[ gow ])
Q COLCOMP2 ]1
[ RATE I value
[
INIT VALUE
J
value [ ENTER \
[
[ ENTER ) [ FINAL VALUE 1 Value [ ENTER ) [_ FINAL TIME J
value [ ENTER
Changing Pressure Ramps
To change pressure ramps for each of the four auxiliary EPC channels, follow the procedure for
setting pressure ramps and enter new values for any of the variables.
Operating Detector Systems 5-9
Example of Setting Pressure Ramps
This example shows how to enter a pressure ramp to program the gases for a detector that is
installed in the A position and controlled by auxiliary channel D.
1. To access auxiliary channel D:
Press:
WmSM
EPP D
PQ
ACTUAL
SETPOINT
10,0
10.0
The GC display looks like this.
2. Enter a pressure program for auxiliary channel D:
a. Press: C INIT VALUE 1 40 [ ENTER 1 to set an initial pressure of 40 psi.
b. Press: C INIT TIME 1 5 [ ENTER 1 to maintain the initial pressure for 5 minutes.
c. Press: [
RATE
1 10 [ ENTER 1 to increase the pressure by 10 psi per minute.
d. Press: [ FINAL VALUE 1
100 ( ENTER 1 to set a final pressure of 100 psi.
e. Press: [ FINAL TIME l
io [ ENTER 1 to maintain the final pressure for 10 minutes.
The system will now ramp the pressure as shown below:
Operating Detector Systems 5-10
Verifying Pressure Ramps
To verify pressure for each of the four auxiliary channels, access the pressure channel to display
the actual and setpoint pressure values. For example:
Press: [1^31$ [
A
I to verify the pressure for auxiliary EPC channel C.
ACTUAL
SETPOINT
60fl
1
The GC display looks like this.
Operating Detector Systems
5-11
Setting Capillary Makeup Gas Flow Rate
Capillary makeup gas is the gas that you add to the detector to compensate for the low carrier
gas flow rates used for capillary columns. Low carrier gas flow must be compensated for
because detectors are designed to operate best with a carrier flow rate of at least 20 ml/min,
which is typical of packed-column GC applications. Carrier flow rates less than 10 ml/min
(typically for capillary GC applications) require capillary makeup gas to ensure a total flow rate
(carrier plus makeup) of at least 20 ml/min.
For the ECD, capillary makeup gas should be used even with HP Series 530 \x capillary columns
because the detector requires high total flow rate (at least 25 ml/min).
Exceptions to Makeup Gas Flow
The TCD requires a total flow rate of only 5 ml/min (with about 15 ml/min TCD reference
flow). For the FID, TCD, NPD, and FPD, HP Series 530 [i capillary columns may be used
without capillary makeup gas as long as the carrier flow rate is between 10 and 20 ml/min. Some
loss of detector sensitivity may occur at lower flow rates.
For the FID, NPD, and FPD, makeup gas is added directly to hydrogen within the detector
flow manifold. For an ECD or TCD, it is added into the column gas stream via a capillary
makeup gas adapter fitted into the detector column inlet.
Operating Detector Systems
5-12
To set the makeup flow rate supply pressure for capillary makeup gas to about 276 kPa (40 psi):
1. Make sure the column and makeup gas fittings (if used) are properly installed.
2. Turn off all gas flows through the detector except the carrier flow.
3. Adjust the column flow to the desired value for the detector and column. Measure the flow
at the detector exit with a bubble flow meter.
4. Use the following instructions to enter the makeup gas values for either manual or EPC
systems:
Manual Pressure Control
a. Set supply pressure for capillary makeup gas to about 276 kPa (40 psi).
b. Open the auxiliary gas on/off valve. Use a small screwdriver to turn the variable
restrictor at the center of the on/off valve as necessary to obtain the desired total flow
rate (column plus makeup).
Variable Restrictor Adjustment
Variable Restrictor
Variable Restrictor
Operating Detector Systems 5-13
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 40 psi.
b. Open the Aux gas (makeup gas) on/off valve completely. You will use the auxiliary EPC
pressure to control the auxiliary gas flow rate. Be sure to open the needle valve fully by
turning it clockwise with a screwdriver.
c. Select the pressure units you would like to use.
To change the units, press: tliaaSll I 1 1 [ ENTER I . Then press the number of the
corresponding unit you want to use:
CD = kPa
d. The example below sets Inlet B (Injector B) pressure to 10 psi. Use the example to set
the pressure you have selected.
e. Press:
i S P f t i l [ INJBPRES j
1 1 1 [ o 1 [ ENTER 1
ACTUAL
EPP B
10.0
Sete inlet B pressure to 10 psi.
SETPOINT
10.0
The GC display looks like this
Note: To keep the flow constant through an oven ramp program, see chapter 10, "Using
Electronic Pressure Control."
f. Adjust the makeup gas pressure to the detector as necessary to obtain 30 ml/min total
flow rate (column plus makeup).
5. Refer to the appropriate detector section to initialize the detector for operation.
Operating Detector Systems
5-14
If the Power Fails..
If the power fails frequently, turn off the detector whenever it is not in use.
Note: When a detector is turned on after being off, it must be given time to stabilize before it
can be used at high sensitivity. The baseline will drift until the detector reaches equilibrium.
When power is restored after a power failure, the detector recovers to the same state as when
the power failed. The active element is restored to "on" if it was on before the power failure.
If the gases used to light the FID or FPD are controlled with EPC, the flow will go to zero when
the power fails and return to setpoint when restored. You will need to relight the flame after
the power is turned on. For auxiliary EPC, the GC returns to the setpoints it had before the
power failed.
Shutting Down Each Day
On a daily basis, use the steps in the following procedure to shut down the detector:
1. In most cases, leave the detector on and at operating temperature to avoid a long equilibration time at startup.
2. Leave the carrier flow on to protect the column(s). For extended shutdown periods, cool the
oven to room temperature, and then turn the carrier flow off.
3. With EPC applications, you can reduce the gas flows to conserve gas and still have the
detector lit and ready.
Note: For more information about the Gas Saver application, see chapter 10, "Using the
Gas Saver Application."
4. With the ECD, you may want to reduce the sensitivity by lowering the temperature to
prolong its lifetime. For extended shutdown periods, cap off the column interface and leave
a small amount of makeup gas flowing through the system.
Operating Detector Systems
5-15
Operating the Flame lonization Detector (FID)
The flame ionization detector (FID) responds to compounds that produce ions when burned in
an H2-air flame. These include all organic compounds, although a few (such as formic acid and
formaldehyde) exhibit poor sensitivity. This selectivity can be advantageous—for example,
when used as solvents, H2O and CS2 do not produce large solvent peaks.
Compounds Producing Little or No Response
Permanent gases
Nitrogen oxides
Silicon halides
H20
NH 3
CO
C0 2
CS 2
02
CCI4
The system is linear for most organic compounds from the minimum detectable limit through
concentrations greater than 107 times the minimum detectable limit. Linear range depends on
each specific compound and is directly proportional to sensitivity of the FID toward the given
compound.
For maximum sensitivity, optimize the flows using standard samples containing components of
interest in expected concentrations. Use the standard to experiment with different carrier, air,
and H2 flow rates, and determine the flow rates giving maximum response.
Operating Detector Systems
5-16
FID
Optimum Response Hydrogen versus Carrier Flow
50
(156)
_
40
(132)
—
30
(107)
—
20
—
Hydrogen Flow
[ml/min or kPa]
(78)
I
20
1
1
30
40
1
50
1
60
Carrier Flow (N2), ml/min
In general, where sample components of interest are in high concentration, increased air flow
may be necessary (up to 650 ml/min). Where components of interest are in low concentration,
reduced air flow rates are acceptable (375 to 425 ml/min).
Setting Up the FID for Operation
To set up the FID for operation, you must do the following:
• Set the flow (for either packed or capillary columns)
•
Set the detector flow rates
• Turn on the detector
• Ignite the flame
FID
Operating Detector Systems
5-17
Hydrogen Flow Rate versus Pressure
80 —
60 —
Hydrogen Flow
[ml/min]
40 —
20 —
50
I
T
100
200
I
250
150
Pressure (kPa)
Air Flow Rate versus Pressure
800 —
600 —
/r
Air Flow
[ml/min]
/X
400 —
200 —
I
100
200
300
I
I
400
500
Pressure (kPa)
Operating Detector Systems
5-18
FID
Setting the FID Flow for Packed Columns
The gas flow rates given in this section ensure good, reliable detector behavior for most
applications. To optimize detector behavior for a specific application, use a standard sample
matched to the application and experimentally try other flow rates.
WARNING
FLAME IONIZATION DETECTORS USE H 2 GAS AS FUEL. IF H 2 FLOW IS
ON AND NO COLUMN IS CONNECTED TO THE DETECTOR INLET
FITTING, H 2 GAS CAN FLOW INTO THE OVEN AND CREATE AN
EXPLOSION HAZARD. INLET FITTINGS MUST HAVE EITHER A
COLUMN OR A CAP CONNECTED AT ALL TIMES THAT H 2 IS SUPPLIED
TO THE INSTRUMENT.
Note: Depending upon the column type used and the analyses to be performed, you may have
to change the jet in the FID.
Use the steps in the following procedure to set the FID flow in a packed column. This
procedure assumes that detector support gases are connected, the system is leak-free, the
correct jet is installed, and a column is installed.
1. Close the Aux Gas on/off valve. This controls the makeup gas.
2. Set the column flow rate to 30 ml/min. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate inlet
system information in Chapter 4.
3. Set the oven and heated zones to the desired operating temperatures.
4. Gently close the on/off controls for H2 and air by turning them clockwise.
5. Using the flow rate versus pressure figures (shown in this section) and the carrier gas flow
rate, set supply pressures for H2 and air to obtain the correct flow rates (30 ml/min of Fb
and 430 ml/min of air are correct for most applications).
You can set H2 and air flow rates simply by setting their respective pressures. However,
if flow rates need to be verified, continue with this section using the bubble flow meter.
Otherwise, open the H2 and air on/off valves by turning them fully counterclockwise, and
proceed to "Igniting the Flame" later in this section.
FID
Operating Detector Systems
5-19
6. Use the following steps to set the H2 flow rate to 30 ml/min:
a. Attach a bubble flow meter to the FID collector.
WARNING
TO MINIMIZE RISK OF EXPLOSION WHEN USING A BUBBLE FLOW
METER, NEVER MEASURE AIR AND H 2 TOGETHER. MEASURE THEM
SEPARATELY.
b. Open the H2 on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus H2) through the detector.
c. Adjust the H2 pressure to the detector to obtain a total flow rate (column plus H2) of
about 30 ml/min.
d. Close the H2 on/off valve.
7. Use the following steps to set the air flow rate to 400 ml/min:
a. Open the air on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus air) through the detector.
b. Adjust the air pressure to the detector to obtain a total flow rate (column plus air) of
about 430 ml/min.
8. Remove the bubble flow meter from the FID collector.
9. Open the H2 on/off valve. Proceed to "Igniting the Flame" later in this chapter.
Operating Detector Systems
5-20
FID
Setting the FID Flow for Capillary Columns
WARNING
FLAME IONIZATION DETECTORS USE H 2 GAS AS FUEL. IF H 2 FLOW IS
ON AND NO COLUMN IS CONNECTED TO THE DETECTOR INLET
FITTING, H 2 GAS CAN FLOW INTO THE OVEN AND CREATE AN
EXPLOSION HAZARD. INLET FITTINGS MUST HAVE EITHER A
COLUMN OR A CAP CONNECTED AT ALL TIMES THAT H 2 IS SUPPLIED
TO THE INSTRUMENT.
Note: Depending upon the column type used and the analyses to be performed, you may have
to change the jet in the FID.
The following table and graph show the optimal flow rates at which to control your FID.
FID
Operating Detector Systems 5-21
Typical Pressure versus Flow for FID Flow Restrictors
Values computed using ambient temperature of 21 °C and pressure of 14.56 psi
FID Makeup
HP pn 19243-60540
Green and Red Dots
Flow Restrictor
Pressure
kPa
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
FID Hydrogen
HP pn 19231-60770
Red Dot
FID Air
HP pn 19231-60610
Brown Dot
Flow (ml/min)
psig
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Nitrogen
Helium
Hydrogen
6.4
7.2
17,0
29.0
44.0
61.0
80.0
100.0
122.0
150.0
178.0
18.0
44.0
77.0
116.0
162.0
211.0
264.0
322.0
383.0
445.0
15.0
26.0
39.0
53.0
69.0
86.0
104.0
123.0
143.0
Air
65.0
157.0
273.0
410.0
561.0
726.0
900.0
1084.0
= Recommended calibration points for using EPC with the HP 3365 ChemStation
FID Restrictors
1000
500
•Hydrogen
400
800
300
600
.E
it
f
_o
200
Helium
Nitrogen
400
^
100
200
20
Operating Detector Systems
40
5-22
60
80
Pressure (psig)
100
120
FID
Use the steps in the following procedure to set the column flow in a capillary column. This
procedure assumes that the detector support gases are connected, the system is leak-free, the
correct jet is installed, and a column is installed.
1. Set the column flow to the desired rate. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate inlet
system information in chapter 4.
2. Set the oven and heated zones to the desired operating temperatures.
3. Adjust the carrier and makeup gas flow rate (column plus makeup) through the detector to
at least 30 ml/min.
4. Use the following steps to set manually or verify the H2 flow rate to approximately
30 ml/min:
WARNING
TO MINIMIZE RISK OF EXPLOSION WHEN USING A BUBBLE FLOW
METER, NEVER MEASURE AIR AND H 2 TOGETHER. MEASURE THEM
SEPARATELY.
a. Attach the bubble flow meter to the FID collector.
b. Open the H2 on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus makeup plus H2) through the detector.
c. Adjust the H2 pressure to the detector to obtain a total flow rate (column plus makeup
plus H2) of about 60 ml/min.
d. Close the H2 on/off valve.
5. Use the following steps to set the air flow rate to 400 ml/min:
a. Open the air on/off valve by turning it counterclockwise. Measure total flow rate
(column plus makeup plus air) through the detector.
b. Adjust the air pressure to the detector to obtain a total flow rate (column plus makeup
plus air) of about 400 ml/min.
FID
Operating Detector Systems
5-23
6. Remove the bubble flow meter from the FID collector.
7. Open the H2 on/off valve and ignite the flame.
8. Use the following instructions to enter the makeup gas values for either manual or
electronic systems.
Manual Pressure Control:
a. Set the supply pressure for the capillary makeup gas to about 276 kPa (40 psi).
b. Open the Aux gas (makeup gas) on/off valve by turning it counterclockwise.
c. Use a small screwdriver to turn the variable restrictor at the center of the on/off valve as
necessary to obtain 30 ml/min total flow rate (column plus makeup).
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 40 psi using the keyboard.
b. Open the Aux gas (makeup gas) on/off valve. Turn the variable restrictor fully
counterclockwise. Then adjust the pressure to set the desired flow rate.
c. Select the pressure units you would like to use.
To change the units, press: i$i®38fl 1 i I I ENTER I . Then press the number of the
corresponding unit you want to use:
d. With auxiliary EPC, makeup gas can be controlled through auxiliary pressure channels
C, D, E, or F from the keyboard. The example below sets the auxiliary channel C
pressure to 10 psi.
Press:
isS$i&gl I
A
1 I
1
1 (~o~^ [ ENTER"!
ACTUAL
EPP C
SETPOINT
10,0
10i
Sets auxiliary channel C pressure to 10 psi.
The GC display looks like this.
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control."
e. Adjust the makeup gas pressure to the detector as necessary to obtain 30 ml/min total
flow rate (column plus makeup).
Operating Detector Systems
5-24
FID
9. Gently close the on/off controls for H2 and air by turning them clockwise.
10. Use the flow rate versus pressure graphs shown earlier in this chapter and the carrier gas
flow rate to set the supply pressures for H2 and air. Set the supply pressures to obtain the
correct flow rates. (30 ml/min of H2 and 400 ml/min of air are correct for most applications.)
Generally, you can set H2 and air flow rates simply by setting their respective pressures. For
an explanation of the relationship of flow to pressure in an EPC system, see chapter 10,
"Using Electronic Pressure Control."
Flow Panel for Controlling FID Operation
On/Off Valve,
Air
On/Off Valve,
H2
FID
Ignitor Button
(press to ignite)
On/Off Valve,
Capillary Makeup Gas
Operating Detector Systems
5-25
Setting the Makeup Gas Flow Rate
Detectors are designed to operate best with a carrier flow rate of at least 20 ml/min, which is
typical of packed-column GC applications. Carrier flow rates of less than 10 ml/min (typically
capillary GC applications) require capillary makeup gas to ensure a total flow rate (carrier plus
makeup) of at least 20 ml/min.
FID sensitivity depends on the ratio of H2 to carrier flow (or carrier plus makeup gas for
capillary columns). Use the procedure described in the following section to obtain maximum
sensitivity.
You can set makeup flow rate manually or electronically. In both cases, good laboratory
practice suggests that you calibrate the system with a bubble flow meter.
To set the makeup flow rate, set the supply pressure for capillary makeup gas to about 276 kPa
(40 psi):
1. Make sure the column and makeup gas fittings (if used) are properly installed.
2. Turn off all gas flows through the detector except the carrier flow.
3. Adjust the column flow to the desired value for the detector and column. Measure the flow
at the detector exit with a bubble flow meter.
4. Use the following instructions to enter the makeup gas values for either manual or
electronic systems.
Manual Pressure Control:
a. Set the supply pressure for the makeup gas to about 276 kPa (40 psi).
b. Open the Aux gas (makeup gas) on/off valve by turning it counterclockwise.
c. Use a small screwdriver to turn the variable restrictor at the center of the on/off valve as
necessary to obtain the desired total flow rate (column plus makeup).
Operating Detector Systems
5-26
FID
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 40 psi using the keyboard.
b. Open the Aux gas (makeup gas) on/off valve. Turn the variable restrictor fully counterclockwise. Then adjust the pressure through the keyboard to set the desired flow rate.
c. Select the pressure units you would like to use.
To change the units, press: fc:*a$3ll ( 1 1 1 ENTER I . Then press the number of the
corresponding unit you want to use:
G Q = bar
d. The example below sets the auxiliary channel C pressure to 10 psi.
Press: fe*%8|i&&fl 1
A
BPP O
\ 1
1
1 LT-Q I [ ENTER!
ACTUAL
SETPOINT
10,0
10.0
Sets auxiliary channel C pressure to 10 psi
The GC display looks like this
Note: To keep the flow constant through an oven ramp program, see chapter 10, "Using
Electronic Pressure Control."
e. Adjust the makeup gas pressure to the detector as necessary to obtain 30 ml/min total
flow rate (column plus makeup).
Turning the FID On and Off
After the FID flows have been set, you can turn on the detector electronics.
To turn the FID on, press:
(or (~B~i)
To turn the FID off, press:
( o r (~B~1 )
FID
Operating Detector Systems
5-27
Igniting the FID Flame
This procedure assumes that detector support gases are connected, the system is leak-free, the
correct jet is installed, a column is installed, and the carrier gas and detector support gases have
been set and verified at the detector exhaust vent.
1. Open the air, H2, and makeup gas on/off valves.
Note: When using He as the capillary makeup gas, it may be necessary to turn off the
makeup gas flow temporarily until the flame is lit.
2. Before pressing the ignitor button, enter the following:
(or
f~B~i
) (~ON~|
SIG 1 1 ( o r [ SIG2 I \ |~~A"1 ( o r [ B J \ [ ENTER 1
SIG1 1 (nrl
SIG 2 1 \
3. Press the ignitor button.
Note: You can light the FID flame regardless of whether the detector is electronically
on or off.
The displayed FID signal level will be in the range from 0 to 0.3 pA. When the flame lights, the
displayed signal increases to some greater steady value (for example, 10 pA), indicating that the
detector is active. The precise value depends upon the column and operating conditions. Turn
makeup gas on if necessary.
You may also test for ignition by holding a cold, shiny surface (such as a chrome-plated wrench)
over the collector exit. Steady condensation indicates that the flame is lit.
Operating Detector Systems
5-28
FID
Operating the Thermal Conductivity Detector (TCD)
This section assumes that all detector support gases are connected, leak-free, and that a column
is installed.
The TCD filament can be permanently damaged if gas flow through the
detector is interrupted while the filament is operating. Make sure the
detector is off whenever changes and adjustments are made affecting
gas flows through the detector.
Also, exposure to O 2 can permanently damage the filament. Make sure
the entire flow system associated with the TCD is leak-free and that
carrier/reference gas sources are uncontaminated before turning on the
detector. Do not use Teflon tubing, either as column material or as gas
supply lines, because it is permeable to O2.
When measuring TCD flow rates, attach a bubble flow meter directly to
the detector exhaust vent using a small piece of rubber tubing as an
adapter.
Note: When measuring TCD flow rates, a bubble flow meter is attached directly to the detector
exhaust vent using a small piece of rubber tubing as an adapter. For convenience, the HP 5890
provides a stopwatch feature (see chapter 4, "Using the Internal Stopwatch").
Flow Panel Controlling TCD Operation
On/Off Valve,
Capillary Makeup Gas
On/Off Valve,
Reference Gas
TCD
Operating Detector Systems 5-29
Setting Up the TCD for Operation
To set up the TCD for operation, you must do the following:
• Set the flow (for either packed or capillary columns).
• Set the carrier gas type.
• Set the sensitivity.
• Turn on the TCD.
This section will also show you how to:
•
Invert TCD polarity.
•
Use single-column compensation (SCC).
Setting the TCD Flow for Packed Columns
The gas flow rates given in this section ensure good, reliable detector behavior for most
applications. To optimize detector behavior for a specific application, use a standard sample
matched to the application and experiment with other flow rates.
Use the steps in the following procedure to set the TCD flow in a packed column. This
procedure assumes that detector support gases are connected, the system is leak-free, and a
column is installed.
1. Set the detector zone temperature to the desired value (30 to 50 °C greater than the
maximum oven temperature to prevent sample condensation).
Press: t PET A TEMP 1 (Or f PET B TEMP 1 ) temp value 1 ENTER 1
2. Set the column flow rate to 30 ml/min. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate inlet
system information in chapter 4.
Note: When measuring column flow rate, make sure the reference gas flow through the
detector is turned off (clockwise).
Operating Detector Systems
5-30
TCD
3. Use the following steps to set the reference gas flow rate.
Note: A good guideline is to set the reference flow rate at 1.5 times the column flow rate.
a. Open the on/off valve for the TCD reference gas flow by turning it counterclockwise.
b. Use a small screwdriver to turn the variable restrictor at the center of the TCD reference
gas on/off valve as necessary to obtain the desired flow rate (45 ml/min is correct when
total flow is 30 ml/min).
4. If not already done, set the carrier gas type and detector sensitivity as discussed later in this
chapter.
Setting the TCD Flow for Capillary Columns
Use the steps in the following procedure to set the TCD flow in a capillary column. The gas
flow rates given in this section ensure good, reliable detector behavior for most applications. To
optimize detector behavior for a specific application, use a standard sample matched to the
application and experiment with other flow rates.
1. Set the detector temperature to the desired value (30 to 50 °C greater than the maximum
oven temperature to prevent sample condensation).
Press: L PET A TEMP 1 (Or [ PET B TEMP 1 ) temp value 1 ENTER 1
2. Set the column flow to 1 to 2 ml/min. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate inlet
system information in chapter 4.
Note: When measuring column flow rate, make sure the reference gas flow through the
detector is turned off (clockwise).
3. Set the makeup gas so that the total flow rate (column plus makeup) through the detector is
5 ml/min. Turn off the reference gas while making this measurement.
When you use makeup gas, you should push the column all the way up into the detector and
then pull it out approximately 1 mm. However, when you use a relatively high flow rate (and
no makeup gas), the column should be only 1 to 2 mm above the ferrule. If you want to
position the column all the way up for maximum inertness, then continue to use makeup gas
and set it to 1 to 2 ml/min.
Because a portion of the column passes through the TCD heated block and into the cell
itself, do not set the zone temperature for the TCD greater than the maximum temperature
allowed for the column. A higher zone temperature may cause column bleed.
TCD
Operating Detector Systems
5-31
4. Use the following instructions to enter the makeup gas values for either manual or
electronic systems. You can also control the TCD reference gas using the same steps used
to control the makeup gas.
Manual Pressure Control:
a. Set the supply pressure for capillary makeup gas to about 276 kPa (40 psi).
b. Open the Aux gas (makeup gas) on/off valve for TCD makeup gas flow by turning it
counterclockwise.
c. Use a small screwdriver to turn the variable restrictor at the center of the TCD makeup
gas as necessary to obtain 5 ml/min.
After the makeup gas is adjusted, the reference gas should be at least three times the
total flow rate from the column plus makeup. Therefore, if the column plus the makeup
flow is 5 ml/min, the reference flow equals 15 ml/min.
d. Open the on/off valve for the TCD reference gas flow by turning it counterclockwise.
e. Use a small screwdriver to turn the variable restrictor at the center of the TCD reference
gas on/off valve as necessary to obtain 15 ml/min.
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 40 psi using the keyboard.
b. Open the Aux gas (makeup gas) on/off valve. Turn the variable restrictor fully counterclockwise. Then set the pressure through the keyboard to get the desired flow rate.
c. Select the pressure units you would like to use.
To change the units, press: P&aa&l I 1 I [ ENTER I . Then press the number of the
corresponding unit you want to use:
d. The example below sets the auxiliary channel C pressure to 10 psi.
Press:
I&8&&S& 1
A
1 I
1
1 1 ° 1 [ ENTER 1
ACTUAL
Sets auxiliary channel C pressure to 10 psi
SETPOINT
The GC display looks like this
e. Adjust the makeup gas pressure to the detector as necessary to obtain 30 ml/min total
flow rate (column plus makeup).
Operating Detector Systems
5-32
TCD
5. Set the reference gas flow rate:
a. Open the on/off valve for the TCD reference gas flow by turning it counterclockwise.
b. Use a small screwdriver to turn the variable restrictor at the center of the TCD reference
gas on/off valve as necessary to obtain the required flow.
6. If it is not already done, set the carrier gas and detector sensitivity as discussed in the
following sections.
Setting the TCD Carrier Gas Type
To optimize the detector sensitivity with respect to the carrier gas used, a switch is provided on
the TCD signal board that is accessed at the top of the instrument under the top right cover.
FILAMENT
LEADS
TEMP
SENSOR
LEADS
GAS
TYPE
I" N2,Ar
tins
SEE MANUAL
TO DISCONNECT
TCD
TCD
Operating Detector Systems
5-33
1. Locate the switch and place it in the position appropriate for the carrier gas used (either
N2, Ar, or He, H2).
2. To ensure the full dynamic range for the TCD, the reference gas (and capillary makeup gas,
if used) must be the same as the carrier gas. Using different gases results in baseline offset.
The TCD filament can be permanently damaged if gas flow through the
detector is interrupted while the detector is on. Make sure that the
detector is off whenever changes and adjustments are made affecting
gas flows through the detector.
Setting the TCD Sensitivity
Two sensitivity (signal amplification) settings are available through the keyboard. The highsensitivity setting increases sensitivity (area counts observed) by a factor of 32 and is usable in
applications where component concentrations are less than 10 percent. Components that are
more concentrated may exceed the output range for the TCD, causing flat-topped peaks. If this
occurs, use the low-sensitivity setting instead.
You can change the sensitivity setting at any time without turning the detector off. Changing
the setting has no effect upon filament lifetime. To set the TCD sensitivity from low to high:
A
| (or I
B
1) IOFM to set the TCD sensitivity to low.
A 1 (or P e l ) ("ON! to set the TCD sensitivity to high.
For information on how to change TCD sensitivity during a run, see chapter 7, "Making a
Run."
Operating Detector Systems
5-34
TCD
Turning the TCD On and Off
The TCD filament can be permanently damaged if gas flow through the
detector is interrupted while the detector is on. Make sure the detector is
off whenever changes/adjustments are made affecting gas flows
through the detector.
After TCD flows have been set, the detector may be turned on.
To turn the TCD on, press: (PET! QT) (Or C D ) C°D •
To turn the TCD off, press: (j^D C D (or C D ) C D •
Allow about 1/2-hour for thermal stabilization (after the oven and zones achieve desired
setpoint values) before using the TCD.
Inverting the TCD Polarity
For information on inverting the TCD signal polarity, refer to chapter 6, "Controlling Signal
Output."
TCD
Operating Detector Systems
5-35
Using Single-Column Compensation (SCC)
Because the TCD operates with only a single column, which is the analytical column,
single-column compensation (SCC) is strongly recommended to achieve optimum baseline
stability, particularly in temperature-programmed operation.
Alternatively, if two TCDs are installed, conventional dual-column compensation may be
performed by defining the output signal as A-B or B-A so as to output a different signal from
the two detectors. This assumes that the two detectors are operated using identical columns,
temperatures, and flow rate conditions.
The HP 5890 allows you to perform a chromatographic blank run (run made with no sample
injected) and stores the data as a baseline profile. The baseline profile must be consistent from
run to run so it can be subtracted from the sample run data to remove baseline drift (usually
caused by column bleed).
Note: Single-column compensation data is valid only for a specific detector and column
combination, operating under defined temperature and gas flow rate conditions. Invalid results
will occur if conditions by which blank run data is collected are different from conditions used
to collect sample run data.
Two separate profiles may be stored as designated by [ COLCOMPI 1 and L COLCOMP2 1 , For
example, you may store one each for two different detectors or two profiles for the same
detector (using different chromatographic conditions).
Note: The ( STOP 1 key is always active during a column compensation run if you need to
abort the run at the HP 5890 GC.
Operating Detector Systems
5-36
TCD
Displaying the Column Compensation Status
The status of column compensation data is displayed by pressing either [
[ COLCOMP2~*1 The figure below shows examples:
COLCOMPI~~1
Or
Typical Column Compensation Status Displays
(Equivalent displays are possible
for COMP 2 and/or detector B)
ACTUAL
COMP
1
-
NO
DATA
ACTUAL
COMP
1
COtoP
1
-
DATA
OK
ACTUAL
TOO
STEEP
ACTUAL
com? 1
WftONG
TIME
SETPOINT
A
SETPOINT
A
SETPOINT
A
No baseline profile data is presently
stored for detector A in COMP 1.
Valid baseline profile data is presently
stored for detector A in COMP 1 .
Change in baseline slope exceeds
maximum value permitted.
Column compensation data may not be
valid.
SETPOINT
A
Column compensation run aborted
prematurely via I STOP >
Column compensation data may
not be valid.
In each display, COMP 1 or COMP 2 echoes the key pressed ([
A or B indicates the assigned detector.
TCD
COLCOMPI J
or [
COLCOMP2
Operating Detector Systems
1).
5-37
Initiating a Column Compensation Run
After entering the oven temperature program to be used for later sample runs, a column
compensation run is initiated by first pressing either [ COLCOMPI~^1 or [ COLCOMP2~^1 to
display current column compensation status and to designate where the new baseline profile is
to be stored.
•
If the desired detector (A or B) is displayed, the column compensation run is initiated
simply by pressing t ENTER >
• If the wrong detector is displayed, press either A or B to assign the desired detector;
then press I ENTER 1 to initiate the column compensation run.
• I • 1 followed by ( ENTER 1 initiates two parallel column compensation runs, using the same
oven temperature program and storing a baseline profile for each of the assigned detectors
simultaneously.
This option is useful for sample analyses made using different detectors and/or columns but
using identical temperature programs.
Note: A device connected via the remote start/HP 5890 ready cable that is started from the
HP 5890 by a normal analytical run is not started by a column compensation run.
Additional details concerning functions available at the remote receptacle are found in the
HP 5890 Series II Site Prep and Installation Manual.
Messages listed in the next figure are displayed either while a column compensation run is in
progress or if there is a problem preventing the compensation run from starting.
Operating Detector Systems
5-38
TCD
Typical Column Compensation Message Displays
SETPOINT
Comp run in progress. In this example, data
from detector A is stored as COMP 1
(accessed via f COLCOMPI p .
SETPOINT
Displayed if an attempt to start a column
compensation run is made while a sample
run is in progress. No column
compensation run is performed.
ACTUAL
SETPOINT
The oven is not on. Once the oven is
switched on, the column compensation
run begins automatically when the oven is
equilibrated at its initial temperature setpoint.
ACTUAL
SETPOINT
An oven temperature program is not defined:
nonzero t RATE l setpoint value(s) must be
entered. The temperature program defined
should be that used for sample runs. No
column compensation run is performed.
ACTUAL
SETPOINT
Chosen detector (either A or B) not
switched on. No column compensation run
is performed.
ACTUAL
SETPOINT
Chosen detector (either A or B) not present.
No column compensation run is performed.
SETPOINT
No detector(s) present. No column
compensation run is performed.
SETPOINT
Occurs if entering new oven temperature
program setpoints is attempted during a
column compensation run. Entries are
ignored. Also occurs if an attempt is made to
start a column compensation run while one
is already in progress. The one in progress
continues to normal completion.
ACTUAL
1
COMP
BLANK
RUN
A
ACTUAL
INVALID
OVEN
NO
DURING
RUN
NOT O N
TEMP
BET A
PROGRAM
NOT ON
NOT
OETA
INSTALLED
ACTUAL
NO
DETECTOR
FOUND
ACTUAL
INVALID
TCD
IH
COMP
BUN
Operating Detector Systems 5-39
A column compensation run terminates automatically at the completion of its oven temperature program. Any existing baseline profile is erased as data for the new baseline profile is
collected and stored.
Note that the oven temperature program for a column compensation run follows setpoint
values for initial time, rate, and final time as in an analytical run. Data is stored, however, only
for rate and final time portions of the temperature program.
A sample run cannot be started via I START 1 while a column compensation run is in progress.
Press: 1 STOP 1 to abort a column compensation run when the baseline profile stored is
probably not valid (because the oven temperature program will not have reached the final
temperature setpoint). A message WRONG TIME is displayed to indicate that a mismatch has
occurred between the expected length of time for the run versus the actual time.
Assigning Column Compensation Data
After baseline data for a given detector is stored as either COMP 1 or COMP 2, the column
compensation data must be assigned to a specific detector signal. During a run, the
compensation data is subtracted from run data for the same detector.
The following key sequence assigns such baseline-corrected data to a particular output channel:
Press: [ SIG 1 1 (Or f SIG2 1) 1 A \ /Or 1 B 1) [ - \ L COLCOMPI 1 (or [ COLCOMP2 J \ [ ENTER 1.
Operating Detector Systems
5-40
TCD
The figure below illustrates the display confirming the assignment:
Typical Display for Column Compensation
ACTUAL
SIGNAL
1
A
-
COMP
SETPOINT
1
Note: No internal verification is given by the HP 5890 to ensure that compensation data
collected on a given detector is assigned later to be subtracted from the same detector via the
above key sequence. If you get strange baseline behavior from subtracting compensation data:
• Compensation data itself is suspected.
• Data acquired from a different detector has been assigned.
• Chromatographic conditions used for sample analyses are different from those used for the
original column compensation run.
After you assign a particular output channel, sample analyses are performed in the usual
manner, the only difference being that the observed baseline should be relatively free of drift.
TCD
Operating Detector Systems
5-41
Operating the Nitrogen-Phosphorus Detector (NPD)
The nitrogen-phosphorus detector (NPD) uses a jet and collector similar to the FID. However,
the collector contains a small alumina cylinder coated with a rubidium salt (the active element),
which is heated electrically, creating a thermionic source. In this environment, nitrogen and
phosphorus containing organic molecules are ionized. The detector collects the ions and
measures the resulting current.
As with an FID, an NPD requires hydrogen and air, but at lower flows. Therefore, normal
FID-type ionizations are minimal, as is response to compounds not containing nitrogen or
phosphorus. Thus, the detector is both sensitive to and selective of compounds containing
nitrogen and/or phosphorus.
The electrical power for heating the active element is supplied through a toroidal transformer
located inside the NPD cover. The toroidal transformer secondary winding is connected
directly to the collector/active element assembly. The electrical heating current passes directly
through the small platinum wire that is also used to position the active element inside the
collector.
The active element of the NPD operates in a very delicate thermal balance that depends on
several different variables. The magnitude of the response of the NPD is a function of the
temperature of the active element and of the active zone around the active element itself.
Because of this temperature dependence, the output of the detector is very sensitive to
anything that affects the temperature of this active zone. Important variables and their effects
include the following:
• Increasing detector temperature increases the active element temperature and the response.
• Increasing the electrical power to the active element increases both the temperature of the
active element and the response.
• Increasing the hydrogen flow increases the temperature of the active element as well as the
size of the active zone around the active element; both effects result in increased response.
• Increasing the air flow to the detector normally cools the active element slightly and
decreases the response. (The change in temperature from altering the air flow is much less
than the change from altering the hydrogen flow.) Increasing the air flow also decreases the
residence time of a given peak in the active zone of the active element and decreases
response.
Operating Detector Systems
5-42
NPD
• Increasing the carrier gas flow cools the active zone slightly and decreases the residence
time of a component in the active zone, which decreases the response.
A hydrogen flow rate that is too high may cause a true flame around the active element. This
would severely overheat the active element and destroy the specific response. An air flow rate
that is too low may quench the background response of the active element, resulting in a
reequilibration time that is too long to establish a proper background response (negative
solvent peaks kill the active element).
Setting Up the NPD for Operation
To set up your NPD, you must do the following:
• Set the flow (for either packed or capillary columns).
• Condition the active element (bead).
• Set the active element power.
• Turn on the NPD.
Flow Panel Controlling NPD Operation
On/Off Valve,
Air
On/Off Valve,
H2 (Hydrogen)
NPD
r
On/Off Valve,
Capillary Makeup
Gas
Operating Detector Systems
5-43
Conditioning the NPD Active Element (Bead)
Condition the NPD active element (bead) when you install a new element or when the detector
has been turned off for a period of time. Conditioning removes water that may have been
absorbed into the active element from humidity in the air. If the active element is electrically
heated too rapidly, the rubidium coating on the active element can fracture and ruin the
collector.
This section assumes that the detector support gases are connected, the system is leak-free, the
correct jet is installed, and a column is installed.
1. Set and turn on the carrier and detector gases.
2. Turn the active element power control fully counterclockwise to set the power to 000.
Note: The locking lever immediately below the control knob is locked in the right-most
position and unlocked in the left-most position.
3. Turn off the power to the detector and the active element by pressing:
4. Set the oven temperature to 50 °C.
5. With the carrier and detector gases flowing, raise the temperature of the detector's
isothermal zone to 220 °C. Allow the collector to condition for at least 30 minutes under
these conditions.
Note: If your detector is exposed to high humidity, condition new collectors for a longer
period (overnight).
After the active element has been dried, initiate the specific NPD response by setting the
power to the active element.
Operating Detector Systems
5-44
NPD
Setting the NPD Active Element (Bead) Power
NPD Active Element (Bead) Power Control
The following procedure sets the correct operating temperature for the active element.
Operating at a temperature higher than the recommended range produces greater sensitivity at
the expense of increased noise and reduced element lifetime with no increase in minimum
detectable limit.
The temperature of the active element in the NPD collector is controlled by a 10-turn rotary
control located below the keyboard. A mechanical counter (000 through 999) registers the
position of the control.
NPD
Operating Detector Systems
5-45
Before setting the active element power, install a column and set the NPD flows as explained
later in this section.
1. Set the heated zones to the desired operating temperatures. Leave the oven at 50 °C.
Note: The temperature of the heated zone should be at least 200 °C.
2. Turn off the power to the detector and the active element by pressing:
WARNING
DO NOT LEAVE THE DETECTOR ON WHILE SETTING THE ACTIVE
ELEMENT POWER; IT MAY OVERHEAT AND BECOME PERMANENTLY
DAMAGED.
3. Set the active element power control to 000 by turning it fully counterclockwise.
Note: The locking lever immediately below the control knob is locked in the right-most
position and unlocked in the left-most position.
4. Before setting the active element power, enter the following:
[ sis 1 1 (or
[
SIG1
[ siG2 1 \
[ A \ (or 1
B
1)
[ ENTER |
1 (or [ SIG2 1) displayed value
The displayed value on the Oven/Det status window is in pA and should be close to zero.
Allow approximately 1 minute for the baseline to stabilize.
5. Increase the element power slowly by turning the active element power control clockwise in
steps of 100 (waiting 1 minute in between steps) until the displayed signal value approaches
the target value. Expect little or no change at first, then a rapid increase as the element
becomes active.
Generally, the detector is adequately sensitive when enough power is supplied to the active
element to display a signal output value in the range of 20-30 pA.
Note: Operational power settings vary depending on the hydrogen and air flow rate, the
detector temperature, contamination, and the desired sensitivity. For the conditions in this
procedure, typical values range from 400—900. The power control can probably be increased
immediately to 300—400 while giving a negligible increase in offset on the detector. As
Operating Detector Systems
5-46
NPD
higher power settings are approached (500—600), increase the power more slowly and
carefully.
If you know the element power setting, bring power slowly to the setting and fine-tune if
necessary. Wait for the baseline to stabilize before setting a final value.
After reaching the proper range of offset, allow the detector to stabilize before expecting
precise measurements. The offset may drift until the active element becomes fully acclimated to the operating conditions. During this period, the apparent sensitivity of the
detector will change.
Setting the NPD Flow for Packed Columns
The gas flow rates outlined in this procedure ensure good, reliable detector behavior for the
majority of analyses. If it is necessary to modify the flow rates for a specific application, use a
standard sample matched to the application and experiment with the flow rates to optimize the
detector's behavior.
WARNING
TO MINIMIZE THE RISK OF EXPLOSION WHEN USING A BUBBLE
FLOW METER, NEVER MEASURE AIR AND HYDROGEN TOGETHER.
MEASURE THEM SEPARATELY.
This section assumes that the detector support gases are connected, the system is leak-free, the
correct jet is installed, and a column is installed.
1. Close the Aux gas on/off valve.
2. Attach a bubble flow meter to the NPD collector using the rubber adapter.
3. Set the column flow to approximately 20 ml/min.
4. Set the oven and the heated zones to the desired operating temperatures.
5. Set the column flow rate to 20 ml/min. Because the procedure for setting the column flow
rate depends on the type of column installed and inlet system used, refer to the information
about the appropriate inlet system in chapter 4, "Setting Inlet System Flow Rates."
NPD
Operating Detector Systems
5-47
6. Use the following steps to set the H2 flow rate to 3 to 4 ml/min:
a. Open the H2 on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus makeup) through the detector.
b. Adjust the H2 pressure to the detector to obtain a total flow rate (H2 plus column) of 23
to 24 ml/min.
c. Turn the H2 off.
7. Use the following steps to set the air flow rate to 100 to 120 ml/min:
a. Open the air on/off valve by turning it counterclockwise. Measure the total flow
(column plus air) through the detector.
b. Adjust the air pressure to the detector to obtain a total flow of 120 to 140 ml/min.
c. Turn the air flow off.
8. Remove the flow measuring adapter and bubble flow meter from the NPD collector.
9. Open the H2 on/off valve.
Operating Detector Systems
5-48
NPD
Setting the NPD Flow for Capillary Columns
The following table and graph show the pressure and flow values for EPC of the NPD.
Typical Pressure versus Flow for FID Flow Restrictors
Values computed using ambient temperature of 21 °C and pressure of 14.56 psi
FID Makeup
HP pn 19243-60540
Green and Red Dots
Flow Restrictor
Pressure
kPa
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
FID Hydrogen
HP pn 19231-60660
Red Dot
FID Air
HP pn 19234-60600
Brown Dot
Flow (ml/min)
psig
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Nitrogen
Helium
Hydrogen
6.4
15,0
26.0
39.0
53.0
69.0
86.0
104.0
123.0
143.0
7.2
17.0
29.0
44.0
61.0
80.0
100.0
122.0
150.0
178.0
2.0
4.6
8.1
12.4
17.0
22.3
Air
21.0
45.0
76.0
110.0
148.0
188.0
229.0
273.0
318.0
363.0
= Recommended calibration points for using EPC with the HP 3365 ChemStation
NPD Restrictors
400
20
300
15 s
E
200
10 £
Helium
Nitrogen
en
o
100
20
NPD
40
60
Pressure (psig)
80
100
120
Operating Detector Systems 5-49
WARNING
TO MINIMIZE THE RISK OF EXPLOSION WHEN USING A BUBBLE
FLOW METER, NEVER MEASURE AIR AND HYDROGEN TOGETHER.
MEASURE THEM SEPARATELY.
This section assumes that the detector support gases are connected, the system is leak-free, the
correct jet is installed, and a column is installed.
1. Set the oven and the heated zones to the desired operating temperatures.
2. Set the column flow rate to the desired value. Because the procedure for setting the column
flow rate depends on the type of column installed and inlet system used, refer to the
information about the appropriate inlet system in chapter 4.
3. Adjust the total carrier and makeup gas flow (column plus makeup) to at least 30 ml/min.
4. Attach a bubble flow meter to the NPD collector using the rubber flow measuring adapter.
5. Use the following steps to set the capillary makeup gas flow rate for either manual or
electronic pressure control.
Manual Pressure Control:
a. Set the supply pressure for the capillary makeup gas to about 276 kPa (40 psi).
b. Open the Aux gas on/off valve by turning it counterclockwise. Measure the total flow
rate (column plus makeup) through the detector.
c. Use a small screwdriver to turn the variable restrictor at the center of the on/off valve to
obtain a total flow rate of 30 ml/min (column plus makeup).
d. Use the following steps to set the H2 flow rate to 3 to 4 ml/min:
i. Open the H2 on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus makeup plus H2) through the detector.
ii. Adjust the H2 pressure to the detector until the total flow reaches 33 to 34 ml/min.
iii. Turn the H2 flow off.
e. Use the following steps to set the air flow rate to 100 to 120 ml/min:
i. Open the air on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus makeup plus air) through the detector.
ii. Adjust the air pressure to the detector until it reaches 100-120 ml/min.
Operating Detector Systems
5-50
NPD
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 40 psi.
b. Open the Aux gas (makeup gas) on/off valve. Turn the variable restrictor valve fully
counterclockwise. Then adjust the pressure to get the desired flow rate.
c. Select the pressure units you would like to use.
To change the units, press: isi^i&gl I i I [ ENTER I . Then press the number of the
corresponding unit you want to use:
d. The example below sets the auxiliary channel C pressure to 10 psi.
Press:
bW$!ii$& I
A
I t
1
) I ° i [ ENTER j
ACTUAL
SETPOINT
10.0
10.0
Sets auxiliary channel C pressure to 10 psi
The GC display looks like this
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control."
e. Adjust the makeup gas pressure to the detector as necessary to obtain 30 ml/min total
flow rate (column plus makeup).
6. Remove the bubble flow meter from the NPD collector.
7. Open the H2 on/off valve.
NPD
Operating Detector Systems
5-51
Turning the NPD On and Off
WARNING
DO NOT LEAVE THE DETECTOR ON WHILE SETTING THE ACTIVE
ELEMENT POWER; IT MAY OVERHEAT AND BE PERMANENTLY
DAMAGED.
To turn the NPD on, press: (PET! (~A~1 (or (~B~1 )
To turn the NPD off, press:
(or
After the oven and zones reach the desired setpoint values, wait an additional V^-hour before
using the NPD.
Operating Detector Systems
5-52
NPD
Optimizing the Performance of the NPD
To optimize the performance of the NPD, you should avoid contamination of the detector and
preserve the lifetime of the active element (bead).
Avoiding Contamination
The slightest contamination can create serious NPD problems. The following list describes
common sources of contamination to avoid:
• Columns and/or glass wool treated with H3PO4 (phosphoric acid)
•
Phosphate-containing detergents
• Cyano-substituted silicone column (such as XE-60 and OV-225)
• Nitrogen-containing liquid phases
• Any liquid phase deactivated for analysis of basic compounds
•
Fingerprints
•
Leak-detection fluids
• Laboratory air
Contamination may affect the performance of an NPD in two ways:
• Positive contamination gives a more positive offset than what would normally result from a
clean system. In response to the positive offset, you may operate the detector with too little
power to the active element. Because the temperature of the active element is less than
normal, the detector appears less sensitive than is desirable.
• Negative contamination quenches the reaction, resulting in decreased sensitivity. Very high
contamination may completely quench all signals from the detector. If this happens, the
apex of a peak is flattened toward the baseline.
NPD
Operating Detector Systems
5-53
Preserving the Lifetime of the Active Element
The lifetime of the active element is reduced by silicon dioxide coating, loss of rubidium salt,
and humidity. Observe the following suggestions to preserve the lifetime of the active element:
• Prevent silicon dioxide from coating the active element. Residual silanizing reagents from
derivatization, and/or bleed from silicone columns, may coat the active element with silicon
dioxide. This decreases ionization efficiency, reducing sensitivity.
If silanizing is necessary, remove excess reagent before injection. Silicone columns should be
well conditioned and loaded less than 5%.
• Do not overheat the active element. Rubidium loss is caused by overheating the active
element, particularly if the element power is on when gas flows are interrupted (especially in
the carrier). You must turn off the detector or reduce the element power to zero when
changing the columns and/or replacing the gas cylinders. Power to the element while the gas
flow is off can destroy an element within a few minutes.
• Use the lowest element power possible, consistent with maintaining sufficient detector
sensitivity and selectivity for the particular analyses.
• Reduce the power to the active element whenever the detector will not be operated for
extended periods of time (such as over the weekend). To determine the proper amount of
power reduction, plot the normal offset and note the displayed zero value (20—30 is in the
normal range). Then reduce the power setting slightly until the displayed zero value (offset)
just goes to zero or to a value close to zero (lower than 5 picoamps). In this way, the
temperature of the active element will be lowered such that there will be little loss of
rubidium, but the active element will still be kept hot enough to prevent contamination
(condensation) while in standby.
•
If you are using the auxiliary EPC channel to control the NPD gases, you can program
hydrogen to a lower value. This cools the bead and thereby extends the bead life.
• Counteract humidity. Humidity adversely affects the lifetime of an element. Keep the
detector warm (100 °C to 150 °C) when it is not in use. Store the collector (including spare
collectors) in a desiccator whenever you remove it from the NPD for an extended period of
time.
•
Recoat or replace an old element. Invest in a recoating kit, which rejuvenates the active
element in an old collector. Also keep a spare collector available as a replacement.
Operating Detector Systems
5-54
NPD
•
Generally, sensitivity and selectivity to nitrogen decreases as the element ages. Phosphorus
response is affected less than nitrogen response.
• Do not remove the seals that cover the NPD during shipments until you are ready to
connect the column and operate the detector. Without the seals, the active element may
become contaminated, which will reduce the collector's effectiveness and possibly ruin the
active element.
Both the detector baseline and sensitivity change with the carrier flow rate due to changes in
the temperature of the active element. This causes baseline drift in pressure-controlled inlet
systems (capillary inlets) while temperature-programming the column. The amount of change in
the detector response is proportional to the ratio of the total column flow change (temperature
sensitive) to the makeup gas flow (not temperature sensitive); that is, total column flow change
divided by makeup gas flow. Adjust the element power after any change in the carrier flow rate.
When the detector is first turned on, its sensitivity and signal level change slowly over several
hours. Therefore, for applications requiring very stable operation, leave the detector on
overnight, lowering the oven temperature to prevent contaminating the active element with
column bleed.
NPD
Operating Detector Systems
5-55
Operating the Electron Capture Detector (ECD)
This section explains how to operate an electron capture detector (ECD). Specifically, it
describes the following:
• The basic operating characteristics of an ECD
•
General issues to consider when using an ECD, including temperature, gases, flow rates,
and background
• Routine detector operating procedures, including setting the column flow, setting the carrier
gas selection switch, setting carrier gas and makeup gas flow rates, and performing daily
startup and shutdown procedures.
WARNING
THE GAS STREAM FROM THE DETECTOR MUST BE VENTED TO A
FUME HOOD TO PREVENT POSSIBLE CONTAMINATION OF THE
LABORATORY WITH RADIOACTIVE MATERIAL. FOR CLEANING
PROCEDURES, SEE "CLEANING THE DETECTOR" IN THIS CHAPTER.
Operating Detector Systems
5-56
ECD
Requirements for USA Owners
WARNING
DETECTOR VENTING MUST BE IN CONFORMANCE WITH THE LATEST
REVISION OF TITLE 10, CODE OF FEDERAL REGULATIONS, PART 20
(INCLUDING APPENDIX B).
THE DETECTOR IS SOLD UNDER GENERAL LICENSE: OWNERS MAY
NOT OPEN THE DETECTOR CELL OR USE SOLVENTS TO CLEAN IT.
ADDITIONAL INFORMATION IS AVAILABLE IN THE PUBLICATION
INFORMATION FOR GENERAL LICENSEES, PUB. NO. 43-5953-1586
(D).
OWNERS OF THIS DETECTOR MUST PERFORM A RADIOACTIVE LEAK
TEST (WIPE TEST) AT LEAST EVERY 6 MONTHS. SEE "TESTING FOR
RADIOACTIVE LEAKS (THE WIPE TEST)" IN THIS CHAPTER.
WARNING
IN THE EXTREMELY UNLIKELY EVENT THAT BOTH THE OVEN AND THE
ECD-HEATED ZONE SHOULD GO INTO THERMAL RUNAWAY
(MAXIMUM, UNCONTROLLED HEATING IN EXCESS OF 400 °C) AT THE
SAME TIME, AND THAT THE ECD REMAINS EXPOSED TO THIS
CONDITION FOR MORE THAN 12 HOURS, TAKE THE FOLLOWING
STEPS:
•
AFTER TURNING OFF THE MAIN POWER AND ALLOWING THE
INSTRUMENT TO COOL, CAP THE ECD INLET AND EXHAUST VENT
OPENINGS. WEAR DISPOSABLE PLASTIC GLOVES AND OBSERVE
NORMAL SAFETY PRECAUTIONS.
•
RETURN THE CELL FOR EXCHANGE FOLLOWING THE DIRECTIONS
INCLUDED WITH THE FORM GENERAL LICENSE CERTIFICATION
(HP PUB. NO. 43-5954-7621, HP PART NUMBER 19233-90750).
EVEN IN THIS VERY UNUSUAL SITUATION, RADIOACTIVE MATERIAL IS
UNLIKELY TO ESCAPE THE CELL. PERMANENT DAMAGE TO THE 63 NI
PLATING WITHIN THE CELL IS POSSIBLE, HOWEVER, SO THE CELL
MUST BE RETURNED FOR EXCHANGE.
ECD
Operating Detector Systems
5-57
Introduction
The electron capture detector (ECD) cell contains 63Ni, a radioactive isotope emitting
high-energy electrons (|3-particles). These undergo repeated collisions with carrier gas
molecules, producing about 100 secondary electrons for each initial p-particle.
Further collisions reduce the energy of these electrons into the thermal range. These
low-energy electrons are then captured by suitable sample molecules, thus reducing the total
electron population within the cell.
Uncaptured electrons are collected periodically by applying short-term voltage pulses to the cell
electrodes. This cell current is measured and compared to a reference current. The pulse
interval is then adjusted to maintain constant cell current.
Therefore pulse rate (frequency) rises when an electron-capturing compound passes
through the cell. The pulse rate is converted to a voltage, which is related to the amount of
electron-capturing material in the cell.
The ECD responds to compounds having an affinity for electrons—for example, halogenated
materials such as pesticides and related compounds. The following table shows expected
sensitivities to different classes of organic compounds.
Operating Detector Systems
5-58
ECD
General Considerations
General ECD Sensitivity to Various Classes of Compounds
Chemical Type
Relative Sensitivity
Hydrocarbons
1
Ethers, esters
10
Aliphatic alcohols, ketones, amines;
mono-CI, mono-F compounds
102
Mono-Br, di-CI and di-F compounds
103
Anhydrides and tri-CI compounds
104
Mono-I, di-Br and nitro compounds
105
Di-I, tri-Br, poly-CI and poly-F compounds
106
The figures in the table are only approximate, and sensitivity varies widely within each group,
depending on the structure of the material. For example, DDT with 5 chlorine atoms per
molecule can be measured in the 1- to 10-picogram range.
Temperature Effects
Some compounds exhibit strong response to detector temperature. The effect may be either
positive or negative. Try different detector temperatures above the oven temperature to
determine the effect on sensitivity. Generally, a detector temperature between 250 and 300 °C
is satisfactory for most applications.
Gases
The ECD is designed for use with either nitrogen or argon-methane as carrier gas. Nitrogen
yields somewhat higher sensitivity with approximately the same minimum detectable limit, but
is also accompanied by higher noise and occasional negative solvent peaks. Argon-methane
gives a greater dynamic range. Use the appropriate switch to select carrier gas type. The ECD
does not operate properly if the switch is set incorrectly.
Because of its high sensitivity, never use the ECD without moisture, chemical, and O2 traps in
carrier and makeup lines. The traps should be in good condition and installed in the carrier gas
supply line and the makeup gas supply. Also, avoid using plastic tubing, which is permeable to
most gases, for all connections. Use clean copper tubing instead.
ECD
Operating Detector Systems
5-59
Columns and Flow Rates
An ECD is normally used to detect compounds that are reactive enough to interact with metal
columns. Therefore, only 1/4-inch packed glass or fused silica capillary columns are recommended with this detector.
Hydrogen carrier gas (with nitrogen makeup gas) gives the best column performance.
Argon-methane can also be used as makeup gas. For most purposes, 50-60 ml/min of makeup
gas is satisfactory, but the rate may be increased to 100 ml/min for very fast runs. Because the
ECD is a concentration-dependent detector, increasing the flow rate reduces sensitivity but can
extend the linear range.
Note: When measuring ECD flow rates, attach a bubble flow meter directly to the detector
exhaust vent using a small piece of rubber tubing as an adapter.
Background
If the ECD becomes contaminated from impurities in the carrier (or makeup) gas or from
column bleed, a significant fraction of detector dynamic range may be lost. In addition, the
output signal becomes noisy.
To check the background level, allow ample time for the components from the previous
analyses to be flushed from the system and then make a blank run (one with no sample
injected).
Setting Up the ECD for Operation
To set up the ECD for operation, you must:
• Set the carrier gas selection switch (if it is not done already)
• Set the ECD flow (for either packed or capillary columns)
Operating Detector Systems
5-60
ECD
Setting the Carrier/Makeup Gas Selection Switch
The carrier gas selection switch is located on the detector board behind the right instrument
side panel. Use the following procedure to set the carrier gas selection switch if necessary:
1. Turn off the power and unplug the instrument.
2. Remove the top right cover by lifting first at its rear edge and then sliding it toward the rear
of the instrument.
3. Remove the right side panel by removing four screws, two along its bottom edge and two
along its top edge.
4. Locate the ECD signal board, which is next to the detector.
5. Locate the N2-AJ-/CH4 switch and place it in the appropriate position based on the type of
predominant gas at the detector (carrier or makeup).
6. Replace the panels.
ECD Carrier Gas Selector Switch
ECD Carrier
Gas Selector
Switch
Up: N2
Down: Ar/CH4
ECD
Operating Detector Systems
5-61
Setting the ECD Flow for Packed Columns
Gas flow rates given in this section ensure good, reliable detector behavior for most
applications. To optimize detector behavior for a specific application, use a standard sample
matched to the application and experiment with other flow rates.
Use the steps in the following procedure to set the ECD flow in the column. This procedure
assumes that the detector support gases are connected, the system is leak-free, and a column is
installed. If your system has electronic pressure control, enter the flows at the keyboard using
the instructions on the following page under "Electronic Pressure Control."
1. Set the column flow to the desired rate. Because the procedure for setting the column flow
rate depends on the column installed and the inlet system in use, refer to the appropriate
system information in chapter 4.
2. Open the ECD Anode Purge On/Off valve. Supply pressure of 30 psi will deliver approximately 3 ml/min of purge flow. ECD anode purge flow is not considered part of total
column flow.
Packed Column Considerations: Either N2 or Ar containing 5% CH4 may be used as carrier
gas. N2 yields somewhat higher sensitivity, but it is accompanied by higher noise; minimum
detectable limit is about the same. N2 sometimes produces a negative solvent peak. A1/CH4
gives greater dynamic range.
Total flow of 60 ml/min is adequate in most applications to prevent peak broadening and
maximize linearity.
The carrier gas must be dry and O2-free. Moisture and O2 traps are strongly recommended for
highest sensitivity. Because plastic tubing is permeable to many gases, the use of clean copper
tubing is recommended for all connections.
Operating Detector Systems
5-62
ECD
Setting the ECD Flow for Capillary Columns
The following table and graph show the optimal pressure and flow values for EPC or the ECD.
Typical Pressure versus Flow for ECD Flow Restrictors
Values computed using ambient
temperature of 21 °C and pressure of 14.56 psi
Flow Restrictor
ECD Makeup
HP pn 19231-60770
Red Dots
Pressure
Flow (ml/min)
kPa
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
psig
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Nitrogen
8.0
20.0
34.0
51.0
69.0
89.0
110.0
132.0
156.0
181.0
Argon-Methane
7.0
17.0
29.0
44.0
60.0
78.0
97.0
117.0
138.0
160.0
= Recommended calibration
points for using EPC with the
HP 3365 ChemStation
Note: The anode purge flow rates will be approximately 1/lOth of the values shown above at the
same pressure settings.
ECD Restrictors
200
Nitrogen
• Argon-Methane
150
1 100
50
20
ECD
40
60
Pressure (psig)
80
100
120
Operating Detector Systems 5-63
To optimize detector behavior for a specific application, use a standard sample matched to the
application and experiment with other flow rates.
Use the steps in the following procedure to set the ECD flow in the column.
1. Set the column flow to the desired rate. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate system
information in chapter 4.
Supply pressure for the makeup gas and anode purge should be set to 207 kPa (30 psi).
2. Open (counterclockwise) the On/Off valve for ECD makeup gas flow. Supply pressure of
60 psi will deliver approximately 60 ml/min of makeup gas flow.
3. Open the ECD Anode Purge On/Off valve. Supply pressure of 60 psi will deliver
approximately 6 ml/min of purge flow. ECD anode purge flow is considered part of total
column flow.
Capillary Column Considerations: H2 or He carrier gas affords the best column performance
with reduced retention times. Ar/CH4 or N2 as makeup gas is used in the range of 60 ml/min.
Because the ECD is a concentration-dependent detector, reduced sensitivity is obtained at
higher flow rates.
For the ECD, capillary makeup gas should be used even with HP Series 530 \x capillary columns
because the detector requires a total flow rate of at least 25 ml/min.
Moisture and O2 traps for carrier and makeup gas are essential with capillary/ECD operation.
Your ECD makeup gas is equipped with either manual or electronic pressure control. Set
the makeup gas according to the instructions for your instrument.
Manual Pressure Control:
a. Set the supply pressure for the capillary makeup gas to about 276 kPa (40 psi).
b. Open the on/off valve for the ECD makeup gas flow by turning it counterclockwise.
c. Use a small screwdriver to turn the variable restrictor at the center of the on/off valve as
necessary to obtain a flow of 60 ml/min.
Operating Detector Systems
5-64
ECD
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 40 psi.
b. Open the Aux gas (makeup gas) on/off valve. You will use the auxiliary EPC pressure to
control the auxiliary gas flow rate.
c. Select the pressure units you would like to use.
To change the units, press: [.. &>!<*.. ]| 1 1 I [ ENTER 1. Then press the number of the
corresponding unit you want to use:
P H = kPa
d. With electronic pressure control, makeup gas is controlled through auxiliary pressure
channels C, D, E, or F from the keyboard. The example below sets the auxiliary channel
C pressure to 40 psi.
p
fe;i£t&&ff:)l
[
A
\ 1
4
I L ° J [ ENTER"!
ACTUAL
SETPOINT
40.0
40.0
Sets auxiliary
channel
C pressure
to 10 p s i
The GC display looks like this
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control."
e. Adjust the makeup gas pressure to the detector as necessary to obtain an appropriate
total flow rate (column plus makeup).
For the ECD, use capillary makeup gas even with HP Series 530 |i capillary columns because
the large cell size requires high total flow rate (at least 50—60 ml/min).
For an ECD, the makeup gas is added into the column effluent stream via a capillary makeup
gas adapter fitted into the detector column inlet.
ECD
Operating Detector Systems
5-65
Testing for Contamination
Because of its very high sensitivity, the ECD is particularly prone to contamination problems,
including contaminants entering the system via the carrier and makeup gas source.
Perform the following procedure whenever a new carrier gas source is installed:
1. With the instrument on and operating normally, cool the oven to ambient temperature, turn
off the detector, turn off carrier flow to the detector, and remove the column to the ECD. If
a capillary column was installed, also remove the makeup gas adapter in the detector base.
2. Disconnect the carrier gas source line at its fitting on the rear of the inlet used.
Note: If your carrier gas is helium or hydrogen (not N2 or Ar-CtLt), then use the makeup
gas, not the carrier gas.
3. Using a Vespel ferrule, and adapters as necessary, connect the carrier source line to the
detector base, including any traps in the line.
4. Set the carrier pressure to about 7 kPa (1 psi) and check for flow through the detector.
5. Leaving the oven door open, enter any temperature for the detector up to 250 °C.
6. Turn on the detector electronics.
7. Assign the ECD to one of the monitored signals.
8. Within 15 minutes, the displayed signal values on the Oven\Det Status window should be
between 40 to 100 (400 to 1,000 Hz); there may be downward drift.
9. If the displayed values are greater than 1,000 Hz, the trap(s) may be at fault. Connect the
carrier gas supply line directly to the detector base and repeat the test. If the values are still
out of range, then the carrier gas supply or the detector may be contaminated. Try a new
tank of N2 or Ar-CH4. If the system is fine, then the gas was contaminated. If not, the cell is
probably dirty and should be exchanged.
Operating Detector Systems
5-66
ECD
Testing for Leaks
Note: This test assumes that the flow system components upstream from the detector are
leak-free.
Use the steps in the following procedure to test for leaks at the ECD:
1. Set the inlet, oven, and detector to ambient temperature and allow time for cooling. Turn
off the detector and carrier flow.
2. Use a vent plug to cap the ECD exhaust vent.
3. Set the carrier gas pressure to an appropriate valve depending on the inlet system you are
using. Open the carrier gas mass flow controller fully to ensure that flow through the system
is available. Allow time for the system to become fully pressurized.
4. Close the carrier gas flow at its source and monitor system pressure.
5. If no pressure drop is observed over a 10-minute period, assume that the system is leak-free.
6. If leakage is observed, use an appropriate electronic leak detector to check for leaks at the
detector column fittings and at the plugged vent.
Note: The detector body itself is not a likely source of leaks. It cannot be disassembled
without special license from the Nuclear Regulatory Commission or Agreement State
Licensing Agency (USA only).
Testing for Radioactive Leaks (the Wipe Test)
ECDs must be tested for radioactive leaks at least every 6 months. Records of tests and results
must be maintained for possible inspection by the Nuclear Regulatory Commission and/or
responsible state agency. More frequent tests may be conducted when necessary.
A wipe test kit, supplied with each new ECD, contains complete instructions for conducting the
test.
ECD
Operating Detector Systems
5-67
Operating the Flame Photometric Detector (FPD)
Flow Panel for Controlling FPD Operation
Ignitor Button
(press to ignite)
On/Off Valve,
Air
On/Off Valve,
Capillary Makeup
Gas
On/Off Valve,
H 2 (Hydrogen)
Setting Up the FPD for Operation
To set up the FPD for operation, you must:
• Set the FPD flow (for either packed or capillary columns)
• Set the FPD sensitivity
• Turn on the FPD
Operating detector Systems
5-68
FPD
Setting the FPD Flow for Packed Columns
The gas flow rates given in this section ensure good, reliable detector behavior for most
applications. To optimize detector behavior for a specific application, use a standard sample
matched to the application and experiment with other flow rates.
WARNING
FLAME PHOTOMETRIC DETECTORS USE HYDROGEN GAS AS FUEL.
IF HYDROGEN FLOW IS ON AND NO COLUMN IS CONNECTED TO THE
DETECTOR INLET FITTING, HYDROGEN GAS CAN FLOW INTO THE
OVEN AND CREATE AN EXPLOSION HAZARD. INLET FITTINGS MUST
HAVE EITHER A COLUMN OR A CAP CONNECTED WHENEVER
HYDROGEN IS SUPPLIED TO THE INSTRUMENT.
Use the steps in the following procedure to set the FPD flow in a packed column. This
procedure assumes that detector support gases are connected, the system is leak-free, and a
column is installed.
1. Close the Aux gas on/off valve.
2. Set the column flow rate to 20 ml/min. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate inlet
system information in chapter 4.
3. Set the oven and heated zones to the desired operating temperatures.
4. Attach a bubble flow meter to the FPD vent tube.
WARNING
TO MINIMIZE RISK OF EXPLOSION WHEN USING A BUBBLE FLOW
METER, NEVER MEASURE AIR AND HYDROGEN TOGETHER.
MEASURE THEM SEPARATELY.
To optimize sulfur sensitivity, use a lower hydrogen flow rate (50—60 ml/min is recommended). To optimize phosphorus sensitivity, use a higher hydrogen flow rate (about 100
ml/min is recommended).
FPD
Operating Detector Systems
5-69
5. Use the following steps to set the H2 flow rate to 75 ml/min:
a. Open the H2 on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus H2) through the detector.
b. Adjust the H2 pressure to the detector to obtain a total flow rate (column plus H2) of
about 95 ml/min.
c. Close the H2 on/off valve.
6. Use the following steps to set the air flow rate to 100 ml/min.
a. Open the air on/off valve by turning it counterclockwise and measure the total flow rate
(column plus air) through the detector.
b. Adjust the air pressure to the detector to obtain a total flow rate (column plus air) to
120 ml/min.
7. Remove the measuring adapter from the FPD collector.
8. Open the H2 on/off valve. To ignite the flame, see "Igniting the FPD Flame" later in this
chapter.
Operating detector Systems
5-70
FPD
Setting the FPD Flow for Capillary Columns
This table and graph show the optimal flow rates at which to control your FPD with EPC.
Typical Pressure versus Flow for FPD Flow Restrictors
Values computed using ambient temperature of 21 °C and pressure of 14.56 psi
FPD Makeup
FPD Hydrogen
FPD Air
HP pn 19234-60570 HP pn 19234-60570
HP pn 19243-60540
Flow Restrictor
Red Dot
Green and Red Dots
Brown Dot
Pressure
Flow (ml/min)
kPa
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
psig
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Nitrogen
Helium
Hydrogen
6.4
15.0
26.0
39.0
53.0
69.0
86.0
104.0
123.0
143.0
7.2
17.0
29.0
44.0
61.0
80.0
100.0
122.0
150.0
178.0
31.0
73.0
126.0
189.0
259.0
336.0
Air
15.0
34.0
57.0
84.0
113.0
143.0
178.0
212.0
248.0
284.0
= Recommended calibration points for using EPC with the HP 3365 ChemStation
FPD Restrictors
20
FPD
40
60
Pressure (psig)
80
100
120
Operating Detector Systems
5-71
The gas flow rates given in this section ensure good, reliable detector behavior for most
applications. To optimize detector behavior for a specific application, use a standard sample
matched to the application and experiment with other flow rates.
WARNING
FLAME PHOTOMETRIC DETECTORS USE HYDROGEN GAS AS FUEL.
IF HYDROGEN FLOW IS ON AND NO COLUMN IS CONNECTED TO THE
DETECTOR INLET FITTING, HYDROGEN GAS CAN FLOW INTO THE
OVEN AND CREATE AN EXPLOSION HAZARD. INLET FITTINGS MUST
HAVE EITHER A COLUMN OR A CAP CONNECTED WHENEVER
HYDROGEN IS SUPPLIED TO THE INSTRUMENT.
Use the steps in the following procedure to set the FPD flow in a capillary column. This
procedure assumes that the detector support gases are connected, the system is leak-free, and a
column is installed.
1. Set the oven and the heated zones to the desired operating temperatures.
2. Set the column flow to the desired rate. Because the procedure for setting column flow rate
depends on the column installed and the inlet system used, refer to the appropriate inlet
system information in chapter 4.
3. Set the carrier and makeup gas flow rate (column plus makeup) through the detector to at
least 20 ml/min.
4. Attach a bubble flow meter to the FPD vent tube.
Your FPD makeup gas is equipped with either manual or electronic pressure control. Set
the makeup gas according to the instructions below. To set capillary makeup gas flow rate:
Manual Pressure Control:
a. Set the supply pressure for the capillary makeup gas to about 276 kPa (40 psi).
b. Open the Aux gas on/off valve for the FPD makeup gas flow by turning it
counterclockwise.
c. Use a small screwdriver to turn the variable restrictor at the center of the Aux gas on/off
valve as necessary to obtain 20 ml/min total flow rate (column plus makeup).
Operating detector Systems
5-72
FPD
Electronic Pressure Control:
a. Set the supply pressure to the auxiliary EPC channel to 60—70 psi using the keyboard.
b. Open the Aux gas (makeup gas) on/off valve. Use the auxiliary EPC pressure to control
the auxiliary gas flow rate.
c. Select the pressure units you would like to use.
To change the units, press: Isis®ft81 I i 1 [ ENTER 1. Then press the number of the
corresponding unit you want to use:
f~3~l = kPa
d. The example below sets the auxiliary channel C pressure to 10 psi.
Sets auxiliary channel C pressure to 10 psi
ACTUAL
SETPOINT
The GC display looks like this
Note: To keep the pressure constant through an oven ramp program, see chapter 10,
"Using Electronic Pressure Control."
e. Adjust the makeup gas pressure to the detector as necessary to obtain 20 ml/min total
flow rate (column plus makeup).
WARNING
TO MINIMIZE RISK OF EXPLOSION WHEN USING A BUBBLE FLOW
METER, NEVER MEASURE AIR AND HYDROGEN TOGETHER.
MEASURE THEM SEPARATELY.
5. Set the H2 flow rate to 75 ml/min. If you have a manually controlled system, use the steps
below. If you have EPC, enter the flow rate from the keyboard as you did for makeup gas.
a. Open the H2 on/off valve by turning it counterclockwise. Measure the total flow rate
(column plus makeup plus detector) through the detector.
b. Adjust the H2 pressure to the detector to obtain a total flow rate (column plus makeup
plus H2) of about 95 ml/min.
c. Close the H2 on/off valve.
FPD
Operating Detector Systems
5-73
6. Use the following steps to set the air flow rate to 100 ml/min:
a. Open the air on/off valve by turning it counterclockwise and measure the total flow rate
(column plus makeup plus air) through the detector.
b. Adjust the air pressure to the detector to obtain a total flow rate (column plus makeup
plus air) to 120 ml/min.
7. Remove the flow measuring adapter from the FPD collector.
8. Open the H2 on/off valve.
Turning the FPD On and Off
After setting the flows, you can turn the FPD on or off.
To turn the FPD on, press: foef! [~A~I (or G Q ) I"ON1 .
To turn the FPD off, press: CDETI (~A~| ( o r C O ) fo^l .
Igniting the FPD Flame
WARNING
TO MINIMIZE THE RISK OF EXPLOSION, DO NOT ATTEMPT TO IGNITE
THE FPD FLAME BY APPLYING A FLAME AT ITS EXHAUST TUBE.
FOLLOW THE PROCEDURE BELOW.
Note: After the flows are set, the FPD flame is relatively easy to ignite. The detector module is
most easily lit if heated to at least 200 °C. Use the sequence described below to avoid a loud
pop on ignition.
1. Turn all FPD flows (except the column flow) off.
2. If required, open the auxiliary N2 valve.
3. Open the air (or O2) valve.
4. Press in and hold the igniter button.
5. Open the H2 valve.
Note: Always open the hydrogen valve after opening the air (or O2) and pressing the igniter.
Failure to do this will result in a loud pop. This should not damage the detector, but is
unpleasant to hear.
Operating detector Systems
5-74
FPD
6. Release the igniter button.
Proper ignition should result in a slightly audible pop. Flame ignition can be verified by
holding a mirror or a cold, shiny surface near the exhaust tube and observing condensation.
Ignition also usually results in a small increase in signal offset on the LED display.
FPD
Operating Detector Systems
5-75
Contents
Chapter 6:
Controlling Signal Output
Assigning a Signal
Displaying or Monitoring a Signal
Zeroing Signal Output
Turning Zero Off/On
Setting Signal Attenuation
Turning Attenuation Off/On
Inverting TCD Signal Polarity
Using Instrument Network (INET)
6-2
6-5
6-7
6-8
6-9
6-12
6-12
6-14
6
Controlling Signal Output
Signal Definition
and Control
Output sources include detector signal(s), heated zone or oven temperatures, carrier gas flow
rates, column compensation run data, or test chromatographic data. If both signal channels are
present, each may output information simultaneously from the same source, or from two
different sources.
Each channel provides two levels of analog output:
0 to +1 mV:
for strip chart recorders.
—0.01 to +1 V:
for electronic integrators with analog inputs.
The two output levels are independent and may be connected simultaneously to separate
data-receiving devices.
Note: A tick mark (electrical pulse) is produced at the +1 mV analog output when either
[ START J or [ STOP 1 is pressed and when a run times out (run time elapses). These marks
locate beginning and ending points in a chromatogram plotted at a continuously running strip
chart recorder.
Controlling Signal Output
6-1
Assigning a Signal
After the appropriate signal channel is displayed by pressing t SIG1 1 (or [ siG2 1, if
Option 550/Accessory 19242A or Option 560/Accessory 19254A is installed), any one of the
instrument functions in the following table may be entered to assign the signal to be output
from the displayed channel.
Note that in a two-channel instrument it is permissible to have the same signal assigned to each
signal channel, allowing identical data to be treated differently simultaneously.
Controlling Signal Output 6-2
Key(s)
Notes
To output the signal from either detector A or detector B
A
or
The message DET A (or B) NOT INSTALLED is displayed if
detector A (or B) is not present.
To output a difference signal between two detectors of the same
type
or
The message DET A (or B) NOT INSTALLED is displayed
if detector A (or B) is not present; the message UNLIKE
DETECTORS is displayed if detectors A and B are not of
the same type.
( ~ ) < COLCOMP1 j j 0o u tp U t a difference signal between a given detector and column
or
and a stored blank run signal for the detector and column
[_^^J
( COLCOMP1
or
[ - \
COL COMP2
o r
T ) r coLcoMP2
1
The message DET A (or B) NOT INSTALLED is displayed if
detector A (or B) is not present.
To output oven temperature
or
or
or
To output stored COMP 1 or COMP 2 data
To output, respectively, inlet A temperature, inlet B temperature,
detector A temperature, or detector B temperature
To output, respectively, carrier gas flow rate A or B
To output a test signal (stored chromatogram) for use in verifying
proper operation of a data-receiving device (integrator, chart
recorder, etc); details are discussed later in this section.
Controlling Signal Output
6-3
As an example, a key sequence to assign detector B data to the Signal 1 output channel would
be:
[ SIG1 I I
B | [ ENTER 1
At the same time, A flow rate data (if electronic sensing is installed) could be assigned to the
Signal 2 output channel:
[ SIG2 | (
7 | [ ENTER 1
As an assignment is made for each channel, confirmation is given through appropriate displays.
Controlling Signal Output 6-4
Displaying or Monitoring a Signal
By pressing the appropriate signal key (t
ing signal channel is displayed.
SIG1
1 or
), current status of the correspond-
Two types of displays are possible: either a display showing the instrument function assigned to
the particular signal channel or a display monitoring the current actual output value for the
assigned instrument function. Repeatedly pressing [ SIG 1 1 (or I SIG2 1) switches between the
two possible display types.
Controlling Signal Output
6-5
Typical Signal Displays:
Detector Signal Assignments:
ACTUAL
SIGNAL 1
Detector Signal Monitoring:
SETPOINT
I
A
ACTUAL
SETPOINT
Z$.7 |
SIGNAL 1
Oven/Zone Temperature Assignment:
ACTUAL
SIGNAL 1
Oven/Zone Temperature Monitoring:
SIGNAL 1
rump
OVEN
ACTUAL
SETPOINT
15998
SIGNAL 1
Flow Rate Assignments:
SETPOINT
ACTUAL
FLOW
SETPOINT
A
Flow Rate Monitoring:
ACTUAL
SIGNAL 1
SETPOINT
30.2
Signal monitoring is useful, for example, in determining if an FID is ignited, in setting active
element current for an NPD, in determining cleanliness of an ECD, in tracking temperatures or
gas flow rates, etc. The monitored value displayed is unaffected by scaling functions performed
by I ZERO
O 1? [ RANGE 2 fri , and/or [ ATTN2T0 "1 (these key functions are discussed later).
If oven or heated zone temperature is monitored via the display, the conversion factor between
the displayed value versus actual temperature is 64 counts/0 C —200. Similarly, if flow rate is
monitored via the display, the conversion factor is 32 counts/(ml/min).
Controlling Signal Output 6-6
Zeroing Signal Output
When using analog signal output, using 1 ZER0 1 can increase dynamic range available by
subtracting a constant background signal from the detector signal. Background signal sources
include the detector itself (background level depending upon detector type), column bleed, or
contaminants in supply gas(es). There are limits to this, however, so it is good practice to
reduce background as much as possible by minimizing column bleed by using clean supply gases
and by performing proper detector maintenance.
Current ( ZER0 ) setpoint value is displayed by pressing the appropriate signal channel key
(t SIG1 1 or ( SIG2 I ), followed by i ZERO 1 (or simply press t ZERO 1 alone, if the desired signal
channel is already displayed). Typical displays are shown below.
Typical Zero Displays
ACTUAL
SETPOINT
104,5
SIG 1 ZERO
ACTUAL
SETPOINT
wmmmmm wmmmmmmmmm
ACTUAL
SETPOINT
ACTUAL
SETPOINT
wmzmmmmmmmmwmmmmm
Once current I ZERO 1 setpoint value is displayed for the desired signal channel, pressing
causes the value to be changed to the current signal value.
Zeroing should be done only at times of quiet chromatographic activity (i.e., not during a run).
To do so during an active run may cause a baseline shift at the recording/integrating device.
If the [ ZERO 1 setpoint value determination is not appropriate for a particular application, any
value from -830000.0 through 830000.0 may be entered at the keyboard.
Entering a value LESS than the current QERCT} value shifts background baseline UPWARD
(but at the expense of available output range); for example, to capture negative peaks or to
compensate for negative baseline drift.
Controlling Signal Output
6-7
Turning Zero Off/On
When the current setpoint offset value for 1 ZER0 1 is displayed for the desired output channel,
pressing 10FF 1 halts subtracting the offset value from the signal. Baseline is restored to its
absolute level with respect to the HP 5890 electrical zero.
• The current setpoint value remains stored; however, pressing 1 0N I resumes subtracting
the offset value from the signal.
• If [ ZERO 1 i s off} pressing [ ENTER 1 switches the zeroing function on and causes a [ ZER0 1
determination.
Controlling Signal Output 6-8
Setting Signal Attenuation
For analytical information from a detector, [RANGE 2T0 ^ and [ ATTN2T0 i are used to keep
peaks of interest on scale at the integrator or chart recorder. Peaks of interest must neither flat
top by exceeding the allowed maximum output level nor be too small to be measured.
[ RANGE 2T0 1 selects and sizes a portion of the full dynamic range for the signal source assigned
to an output channel. The portion selected is sized such that the highest possible value for the
portion does not exceed maximum output voltage allowed for the given output (+1 mV or
+ 1 V).
[ ATTN2T0 1 further selects and sizes a portion of the ranged signal for the +1 mV output to
ensure that the signal does not exceed +1 mV.
Note: [ ATTN2T0 J functions only for the strip chart recorder output (+1 mV) and acts on the
signal AFTER it has been ranged by [ RANGE 2T0 ^i.
For strip chart recorders (analog signal output +1 mV): is attenuated via CHANGE 2to J and
[ ATTN2T0 1. For [ATTN2TO i , each step to a higher value reduces the output signal level
(as defined by t RANGE 2T0 ' j ) by half.
Signal
+ 1 mV Output Level =
[ RANGE 2t() 1
[ ATTN2t()
2
2
For electronic integrators (analog signal output +1 V): is attenuated via [RANGE 2T0 1 from the
HP 5890 and must be set at the integrator. Each step to a higher setpoint value decreases the
output signal level by a factor of 2 (half the previous level).
Signal
+ 1 V Output Level =
[RANGE2T()
1
2
As an example, a key sequence set attenuation and/or range would be:
SIG1 |
or
[ SIG2 |
[ RANGE 2 T ( ) ~ ^
<Vdlue>
t ENTER
SIGI I
or
( SIG2 |
[ ATTN2T0
<value>
t ENTER 1
J
Controlling Signal Output
6-9
The table below gives values permitted for either function, and the output affected.
Valid Setpoints For
Permitted
Setpoints
Key
C RANGE 2T0
1
And
[ATTN2TO
Affected Output
t RANGE 2T0 1
Oto 13
B0TH+1mV&+1 V
(ATTN2Tt?
Oto 10
0NLY+1mV
I
1
Generally, if both an integrator or A/D converter (+1 V output) and chart recorder
(+1 mV output) are connected to the same signal channel, [RANGE 2 t o ^ l should be set properly
first for the integrator or computer, then [ ATTN2T0 1 set appropriately for the chart recorder.
To minimize integration error for an integrator or A/D converter, [RANGE 2T0 1 should normally
be set to the lowest value possible, provided the largest peaks of interest do not exceed 1 volt.
Attenuation functions at the integrating device or computer are then used to ensure that
plotted peaks remain on scale.
Controlling Signal Output 6-10
The table below lists maximum detector output producing +1 volt at the + IV output for each
[RANGE2J()
J setpoint value.
Maximum Detector Signal
Producing + 1 V Output
1
1
[RANGE2f()
|
FID & NPD (pA)
TCD (mV,
High Gain)
1
1
TCD (mV,
Low Gain)
ECD (kHz)
0
1.0x10 3
25
800
10
1
2.0x10 3
50
D
20
2
4.0 x10 3
D
D
40
3
8.0 x10 3
D
D
80
4
1.6x10 4
D
D
160
5
3.2x104
D
D
320
6
6.4 x10 4
D
D
D
7
1.3x105
D
D
D
8
2.6x105
D
D
D
9
5.1x105
D
D
D
10
1.0x106
D
D
D
11
2.0 x10 6
D
D
D
12
4.1x106
D
D
D
13
8.2x106
D
D
D
From the table above, note that for a TCD, [ RANGE 2T0 1 = 0 is suitable for virtually all
applications because the entire linear output range of the detector is included. Likewise,
[RANGE 2T(i~~H settings from 0 through 5 cover the entire useful output range for an ECD. Only
an FID or NPD may require use of the higher [RANGE 2T0 1 settings.
Controlling Signal Output
6-11
Turning Attenuation Off/On
The -(-1 mV strip chart recorder signal output can be switched off, providing no signal to the
data-receiving device. This is often useful in setting the zero position at a connected strip chart
recorder.
This is done through the following key sequence:
[ SIG1 1 o r [ SIG2 I
[ ATTN2T0
J [OFF \
After setting the pen to the desired zero position at the connected chart recorder, the current
attenuation value is restored by pressing 1 0N 1.
Entering a new [ ATTN2T0 ^ value overrides OFF.
Inverting TCD Signal Polarity
Note: Expect a baseline shift any time signal polarity is inverted. This may require a baseline
reset at a connected integrator or chart recorder.
TCD output is ONE signal representing thermal conductivity difference between two flows
(column effluent and reference gas).
• Enter the key sequence:
to assign the signal to an output channel (either A or B).
•
For components giving NEGATIVE-going peaks,
fpETi (~A~I (or (~B~> )
r n
inverts detector output polarity.
Repeating the entry (or simply pressing I - > again if the TCD is still displayed) inverts polarity
again to its original state.
Controlling Signal Output 6-12
Where a given sample has components giving both positive- and negative-going peaks, a
timetable command can be used to invert detector polarity during a run.
For example, to create a timetable event to invert TCD polarity at 1 minute into a run, enter
the key sequence:
either detector
I A \ or
\
Repeating the entry later in the run inverts polarity again to its original state.
Polarity returns to its original state automatically at the end of the run.
Controlling Signal Output
6-13
Using Instrument Network (INET)
The "Instrument Network" (INET) is a path for various devices to communicate with each
other (data and/or commands). INET permits a group of devices (consisting of a "controller"
and some number of data "Producers" and data "Consumers") to function as a single, unified
system.
In using the INET function, chromatographic parameters are entered normally through the
HP 5890 keyboard. Integration parameters are entered at the controller. Parameters for other
devices on the INET loop may be entered at the controller or at their own keyboards.
Collectively, the separate sets of parameters constitute a single set of parameters for an
"analysis."
In DEFAULT operation, the HP 5890 supplies ONLY "Signal 1" data to the INET loop. That
is, HP 5890 data supplied to the INET loop is defined according to the assignment made via
I SIG1 1 To use "Signal 2" data instead, signal reassignment is done at the HP 5890.
As an example, a key sequence to assign detector B data to the Signal 1 output channel would
be:
For more information about INET, refer to the HP 5890 SERIES II Reference Manual and the
reference manuals for your HP integrator/controller.
Controlling Signal Output 6-14
Contents
Chapter 7:
Making a Run
Starting/Stopping a Run
INET Start/Stop Operation
Status LEDs
Using the Time Key
Using Single-Column Compensation
Displaying Column Compensation Status
Initiating a Column Compensation Run
Assigning Column Compensation Data
Using Instrument Network (INET)
Using Timetable Events
Turning Valves On/Off During a Run
Switching Signals During a Run
Changing TCD Sensitivity During a Run
Modifying Timetable Events
7-1
7-1
7-2
7-6
7-8
7-9
7-10
7-12
7-14
7-15
7-18
7-20
7-22
7-23
7
Making a Run
This chapter includes information regarding starting and stopping an analytical run, using
timetable events, and making a single-column compensation (SCC) run.
Starting/Stopping a Run
Pressing ( START > starts the oven temperature program, run clock, and timed events.
Also, a remote start relay is momentarily closed to start a remote device such as an integrator.
For a strip chart recorder, a tick mark is produced to mark the beginning of a run.
Pressing I START > lights the green RUN LED. Yellow OVEN LEDs are lit to follow progress
through an oven temperature program. The red NOT READY LED lights during a run ONLY
if some part of the system becomes not ready (see STATUS LEDs on next page).
[ START 1 aborts a keyboard entry in progress by causing a run to begin immediately. [ START )
itself is inactive if the RUN LED is on or blinking.
Pressing t STOP 1 terminates a run. For a strip chart recorder, a tick mark is produced to mark
the end of a run.
INET Start/Stop Operation
Normally, when the HP 5890 SERIES II (hereafter referred to as HP 5890) and integrator/
controller are connected together via INET, t START 1 and I ST0P 1 on either instrument are
equivalent. The only exception to this is if INET is turned OFF (LOCAL) at the HP 5890:
if INET is off, HP 5890 ( START ) a n d [ STOP ) k e y s a r e independent of those on the
integrator/controller. This permits starting the HP 5890 without simultaneously starting the
integrator/controller. (See the HP 5890 SERIES II Reference Manual for details regarding
switching INET on or off).
Note: The HP 5890 ( STOP 1 key is always active during a run if the run must be aborted at the
HP 5890.
Making a Run
7-1
Status LEDs
Readiness occurs when the oven is on and at its setpoint temperature, when heated zones that
are on are at their respective setpoint temperatures, and when any detector assigned to an
output signal channel is ON.
Any temperature not at setpoint causes the red NOT READY LED to be lit until setpoint is
achieved.
In addition, there is an external readiness input, and an INET readiness input. If a connected
external device is not ready, the NOT READY LED is lit.
If the NOT READY LED is continuously lit, any item(s) preventing readiness can be determined by pressing t CLEAR > : the display cycles, giving an appropriate message for each item.
Making a Run
7-2
Typical NOT READY Displays (obtained by pressing t CLEAR 1 )
CLEAR I Displays
Outside a Run:
ACTUAL
OVEN TEMP
NOT
\M
NOT
SETPOINT
READY
ACTUAL
A
TEMP
ACTUAL
DET A
TEMP
NOT
NOT
ON
NOT
SETPOINT
Assigned detector not turned
on
NOT
SETPOINT
READY
ACTUAL
SYSTEM
SETPOINT
(SIG 1}
ACTUAL
EXT DEVICE
- Temperature not at setpoint
READY
ACTUAL
DET A
SETPOINT
READY
Device external to HP 5890
signals not ready
SETPOINT
INIT system reports not ready
READY
During a Run:
ACTUAL
mn
IN
1
Analytical run currently in
process
PROGRESS
ACTUAL
COMP
SETPOINT
BLANK
RUN
SETPOINT
A
Column compensation run
currently in progress
Note that the figure above shows typical normal displays occurring when various parts of a
properly operating HP 5890 system are not ready for initiating a run.
Making a Run
7-3
HP 5890 READY Display
SETPOINT
HP $090
SYSTEM
READY
For the oven and heated zones, their messages cease to be displayed once their respective
setpoint temperatures are reached. Once every item is ready, pressing i CLEAR I results in the
display shown above.
Status LED Display
On
O
Off
'
"RUN" LED
LED on: indicates a run (either analytical or column compensation) is actively in progress.
LED off: indicates no run currently in progress.
(3
Making a Run
7-4
LED blinking: waiting for HP 5890 readiness. A command
for a remote controlling device has been sent to start a run,
or a column compensation run is initiated, before the
HP 5890 is ready. Run begins automatically once readiness
is achieved.
STATUS LED Displays {cont.)
"NOT READY" LED
LED on: One or more parts of the HP 5890 system reports not
ready. (CTEAR) displays what is not ready.
LED off: HP 5890 system is ready for initiating a run (either analytical
or column compensation) at any time.
LED blinking: Hardware fault.
i
displays FAULT: messages.
i
The RUN LED is normally lit continuously whenever a run is in progress (either an analytical
or column compensation) and off when not in a run. It flashes when a column compensation
run is initiated before the HP 5890 is ready (e.g., oven or zones not at setpoint); the compensation run begins automatically upon readiness.
The RUN LED also flashes on and off in an INET-controlled system in automated operation
during times when the HP 5890 is waiting for some device in the system to complete its task
before starting the run (e.g., while waiting for automatic sampler operation, report printing,
computations, etc). Once the run begins, the LED is continuously lit.
Making a Run
7-5
Using the Time Key
Successively pressing! TIME \ by itself displays various times related to analyses being performed
and also accesses a stopwatch timer useful in setting gas flow rates, measuring elapsed time
between events of interest, etc.
Typical time displays are shown in the figure below. Note that there are three possible functions
outside an analytical run (or column compensation run) and three possible during an analytical
run (or column compensation run). Each press of ( TIME 1 rolls to the next function.
Typical Time Displays
1 Outside a Run: 1
ACTUAL
NEXT
SETPOINT
MIN
RUN
ACTUAL
SETPOINT
ACTUAL
SETPOINT
15.77
mm
ACTUAL
SETPOINT
I=S;10,7
LAST
RUN
1 During a Run: 1
REMAINING
1&77
ACTUAL
1=
1:60,7
SETPOINT
0.64
ACTUAL
ElAPSBD
MIN
ia.i$
SETPOINT
MIN
Time displayed for NEXT RUN or LAST RUN does NOT include [ EQUIBTIME l > and does not
include cooldown time after completing an oven temperature program. It is simply total time
calculated for the analytical (or column compensation run) itself.
In stopwatch mode, both time (to 0.1 second) and reciprocal time (to 0.01 min" 1 ) are displayed
simultaneously. The timer is started by pressing! ENTER It it is stopped by pressing! ENTER I again.
Pressing [ CLEAR 1 AFTER the timer is stopped resets the timer.
Making a Run
7-6
Note that other instrument functions may be accessed normally (e.g., C OVENTEMPJ Or
without stopping or resetting the timer simply by pressing the necessary keys. The timer
continues to run but is not displayed until t TIME 1 is again pressed.
[ T|ME 1 is also used in key sequences to time-program events during a analytical run (see" Using
Timetable Events" in this chapter).
Making a Run
7-7
Using Single-Column Compensation
The HP 5890 permits performing a chromatographic blank run (run made with no sample
injected), storing the data as a baseline profile.
Assuming the baseline profile is consistent from run to run, it may be subtracted from sample
run data to remove baseline drift (usually caused by column bleed).
Note: Single-column compensation data is valid only for a specific detector and column
combination operating under defined temperature and gas flow rate conditions. Invalid results
may occur if conditions by which blank run data is collected are different from conditions used
to collect sample run data.
Two separate profiles may be stored (designated by [ COLCOMPI l or [ COLCOMP2 IV as, for
example, one each for two different detectors or two profiles for the same detector but using
different chromatographic conditions.
Note: The HP 5890 t STOp 1 key is always active during a column compensation run if the run
must be aborted at the HP 5890.
Making a Run
7-8
Displaying Column Compensation Status
Status of column compensation data is displayed by pressing either [ COLCOMPT^I
[ COL COMP2~^| . The figure below gives typical displays:
Or
Typical Column Compensation Status Displays
(Equivalent displays are possible
for COMP 2 and/or detector B)
ACTUAL
COMP
1
-
NO
DATA
SETPOINT
A
ACTUAL
COMP
1
COMP
1
-
DATA
OK
SETPOINT
A
ACTUAL
TOO
STEEP
ACTUAL
COMP
1
WflONG
TIME
SETPOINT
A
No baseline profile data is presently
stored for detector A in COMP 1.
Valid baseline profile data is presently
stored for detector A in COMP 1.
Change in baseline slope exceeds
maximum value permitted.
Column compensation data may not be
valid.
SETPOINT
A
Column compensation run aborted
prematurely via t STOP I
Column compensation data may not be
valid.
In each display, COMP 1 or COMP 2 echoes the key pressed (f COL COMPILE or I COLCOMP2^|
respectively); A or B indicates the assigned detector.
Making a Run
7-9
Initiating a Column Compensation Run
After entering the oven temperature program to be used for later sample runs, a column
compensation run is initiated by first pressing either [ COLCOMPI~^| Or [ COLCOMP2 1 to display
current column compensation status and to designate where the new baseline profile is to be
stored.
•
If the desired detector (A or B) is displayed, the column compensation run is
initiated simply by pressing ( ENTER 1
•
If the wrong detector is displayed, press either A or B to assign the desired
detector, then press [ ENTER \ to initiate the column compensation run.
•
I • 1 followed by [ ENTER 1 initiates two parallel column compensation runs using
the same oven temperature program and storing a baseline profile for each of the
assigned detectors simultaneously.
This option is useful for sample analyses made using different detectors and/or columns but
using identical temperature programs.
Note: A device connected via the remote start/HP 5890 ready cable that is started from the
HP 5890 by a normal analytical run is NOT started by a column compensation run.
Additional detail concerning functions available at the REMOTE receptacle is found in the
HP 5890 SERIES II Site Prep and Installation Manual.
Messages listed in the next figure are displayed either while a column compensation run is in
progress or if there is a problem preventing the compensation run from starting.
Making a Run
7-10
Typical Column Compensation
Message Displays
ACTUAL
1
COUP
BLANK
RUN
SETPOINT
A
ACTUAL
INVALID
OVEN
NO
DURING
RUN
ACTUAL
SETPOINT
ACTUAL
SETPOINT
NOT ON
TEMP
PROGRAM
ACTUAL
DET A
NOT
\H
Or detector B, chosen detector not present.
No column compensation run is performed.
SETPOINT
No detector(s) present. No column compensation run is performed.
FOUND
ACTUAL
INVALID
An oven temperature program is not defined:
nnn7firn( RATE l setpoint value(s) must be
entered. The temperature program defined
should be that used for sample runs. No
column compensation run is performed.
SETPOINT
INSTALLED
ACTUAL
DETECTOR
The oven is not on. Once the oven is
switched on, the column compensation run
begins automatically when the oven is equilibrated at its initial temperature setpoint.
Or detector B, chosen detector not switched
on. No column compensation run is performed.
NOT ON
0ETA
Displayed if an attempt to start a column
compensation run is made while a sample
run is in progress. No column compensation run is performed.
SETPOINT
ACTUAL
NO
SETPOINT
Comp run in progress. In this example,
data from detector A is stored as COMP 1
(accessed via i COLCOMPI 1 ) .
COMP
SETPOINT
RUMt
Occurs if entering new oven temperature
program setpoints is attempted during a
column compensation run. Entries are
ignored. Also occurs if an attempt is made
to start a column compensation run while
one is already in progress. The one in progress continues to normal completion.
Making a Run
7-11
A column compensation run terminates automatically at completion of its oven temperature
program. Any existing baseline profile is erased as data for the new baseline profile is collected
and stored.
Note that the oven temperature program for a column compensation run follows setpoint
values for [ INITTIME ~ ^ f [ RATE 1 a n ( j [ FINAL TIME^I as in an analytical run. Data is stored,
however, only for I RATE 1 and [ FINAL TIME 1 portions of the temperature program.
A sample run cannot be started (via f START 1) while a column compensation run is in progress.
[ STOP 1 aborts a column compensation run: The baseline profile stored is probably not valid
because the oven temperature program will not have reached the [ FINAL TEMP 1 setpoint.
A message WRONG TIME is displayed to indicate a mismatch has occurred between the
expected length of time for the run versus the actual time.
Assigning Column Compensation Data
After baseline data for a given detector (A or B) is stored as either COMP 1 or COMP 2, the
column compensation data must be assigned to a specific detector signal. During a run, the
compensation data is subtracted from run data for the SAME detector.
The following key sequence assigns such baseline-corrected data to a particular output channel:
[ COLCOMP 1 J
SIG1 1 1 A \
1 -
\ [ COL COMP 1 1
OF [ COLCOMP2
[ ENTER
The figure below illustrates the resulting display confirming the assignment:
Making a Run
7-12
J
Column Compensation, Typical Display
ACTUAL
SIGNAL
1
A
-
COMP
SETPOINT
1
Note: There is NO internal verification by the HP 5890 to ensure that compensation data
collected on a given detector is later assigned to be subtracted from the SAME detector via the
above key sequence. If subtracting compensation data results in strange baseline behavior:
•
Compensation data itself is suspected.
•
Data acquired from a different detector has been assigned.
•
Chromatographic conditions used for sample analyses are different from those used
for the original column compensation run.
Once assignment is made to a particular output channel, sample analyses are performed in the
usual manner; the only difference is that the observed baseline should be relatively free of drift.
Making a Run
7-13
Using Instrument Network (INET)
Information about INET communications is available in chapter 6, "Controlling Signal Output"
and in the reference manuals for your integrator/controller.
Making a Run
7-14
Using Timetable Events
Timetable events are controlled through the keys shown.
Timetable Control Keys
TIME
TABLE
OVEN
TEMP
INIT
VALUE
ADD
DELETE
PREV
NEXT
INIT
TIME
RATE
FINAL
VALUE
FINAL
TIME
The following is a list of HP 5890 events that can be controlled during a run.
•
Valves (On/Off)
•
Signal Switching (On/Off)
•
Changing TCD Sensitivity (High or Low)
•
Inverting TCD Polarity (—),Refer to chapter 6, "Inverting TCD Signal Polarity"
•
Split/Splitless Purge Flow On/Off, Refer to chapter 4, "Setting Splitless Mode
Flow "
Valves, signal switching and changing TCD sensitivity are covered in this section. Refer to
chapter 6 for information regarding inverting TCD polarity during a run. Refer to chapter 4
for information regarding turning split/splitless flow on/off during a run.
Making a Run 7-15
ACTUAL
SETPOINT
H®M> OF TIMETABLE
Use the table key to enter into the timetable. From
here, previous and next keys may be used to scroll
through an existing timetable. Add and delete keys
may be used to add or delete timetable commands.
After the TABLE key is pressed to enter the
timetable, use the ADD key to enter a timed
event. The timetable can hold up to 37
timed events.
After the TABLE key is pressed to enter
the timetable, use the DELETE key to remove a timed event.
I
PREVIOUS
1
After the TABLE key is pressed to enter
the timetable, use the PREVIOUS key to
scroll through the timetable toward the
HEAD OF TIMETABLE.
After the TABLE key is pressed to enter
the timetable, use the NEXT key to scroll -^
through the timetable toward the END OF 37
TIMETABLE.
EAR~| After timetable entries have been made, (or
whenever working inside the timetable) use the
CLEAR key to exit timetable programming.
Note: The clear key does not delete any timetable events.
Making a Run
7-16
END OF TIMETABLE
An example key sequence to create a timetable event:
QNI
/
l [ TABLE i
I ADD!
function key
action key
or (OFF"
^
1 TIME I
time value
1 ENTER
1
C PURGE/VALVE i (Valve 1 , 2, 3 or 4 )
Signal Switch = 1 S|G1 I or l siG2 1
TCP SENS
1
CLEAR 1 exits the timetable and returns the keyboard to normal operation
Note: Refer to "Inverting TCD Signal Polarity"
in chapter 6 for time programming TCD polarity.
Making a Run
7-17
Turning Valves On/Off During a Run
For information on controlling splitless purge flow during a run, refer to chapter 4, "Setting
Splitless Mode Flow".
Control of up to four gas/liquid sampling valves (designated as valve 1, 2, 3, and 4) may occur in
either of two ways. The operator may switch the valves manually whenever it is desirable via
keyboard entry, or more conveniently, the valves can be switched ON and OFF during a run via
the HP 5890's timed events table.
For example, to create a timetable event to turn valve 2 on at 1 minute into a run, enter the key
sequence:
1 , 2 , 3 or 4
f~QN~l or
\
/
Note: If the valve is already in the position where a command instructs it to switch, no action
will occur.
The designated channels (1, 2, 3, or 4) are determined solely by the wiring connections to the
valve box.
A valve will reset automatically at the end of each run if a valve timetable is set. If the last
switching mispositioned the valve and the valve does not reset, reset the valve position
manually before starting a new run.
Making a Run
7-18
One way of resetting the valve automatically after the useful run time is to program the valve.
For example, on a two-valve system, where valve 1 is a gas sampling valve and valve 2 is used for
venting, it may be desirable to: 1) inject from valve 1 at the beginning of the run (run time
0.00); 2) vent the last part of the sample, using valve 2, at 2-3/4 minutes (run time 2.75); or
3) relax both valves just prior to the end of the run (determined to be a run time of 40.00).
To perform the above example, enter the following commands:
TABLE 1 | ADD | Q
PURGE/VALVE
Making a Run
7-19
Switching Signals During a Run
Some analyses require the use of more than one detector to completely characterize a given
sample. In situations were the analytical system can be configured to avoid coelution, switch
signals during a run to integrate the output into a single channel system. Signal switching can
be accessed only as a timetable event.
Switching signals replaces the t SIG1
for a specified period of time.
definition to whatever is currently assigned to t
[ RANGE 2T()
[ATTN2TO
RANGE2t()
[ ATTN2TO
I
1
Signal Switch On Time
Signal Switch Off Time
Run Time
Note:
The t ATTN2"O
icey on the HP 5890 has no effect when using an
electronic integrator. Attenuation is controlled locally at the integrator.
Making a Run 7 - 2 0
SIG2
For example, to create a timetable event to switch signals at 1 minute into a run, enter the key
sequence:
or
During a run, at the signal switch on time, ( SIG7^> will switch automatically to monitoring the
device assigned tr>[ siG2 \ The run will continue in this manner until a signal switch off time is
reached or the run ends. Signal assignments reset automatically at the end of each run.
Depending on the analyses, baseline upsets may be seen when signals are switched. These
upsets will become more of a problem when high sensitivity is required. Adjust [ ATTN2T0 J,
if necessary to minimize the upset.
Making a Run
7-21
Changing TCD Sensitivity During a Run
Two TCD sensitivity (signal amplification) settings are available, controlled through the keyboard
<foN~| =HI and P^H =LOW).
The high-sensitivity setting increases sensitivity (area counts observed) by a factor of 32 and is
usable in applications where component concentrations are < 10%.
Components that are more concentrated may exceed the output range for the TCD, causing flattopped peaks. If this occurs, the low sensitivity setting should be used instead.
The sensitivity setting may be changed from one setting to the other at any time during a run
through a timetable event.
For example, to create a timetable event to change the TCD sensitivity from Low to Hi
at 1 minute into a run:
either detector I A I or H E
Low =
\
TABLE 1
| ADD |
(
TCD SENS
1
/
I
A 1
| ON )
[
TIME
Sensitivity returns to its original state automatically at the end of the run.
Making a Run
7-22
High = C2L
Modifying Timetable Events
Example Timetable Event
FUNCTION
TIME
1
i
VAtVE 1
1.00 |
ON
Timetable events can be changed in three ways: by adding new entries, by deleting existing
entries or by modifying the time value of a timed event.
New entries are added by using the same key sequences used to create a table in the first place:
jjl;:&i3&8;| [ TABLE 1 [ADD)
followed by a valid timetable event
To delete a single timetable event, first display the event by pressing:
E§;i%S1 ( TABLE 1
(followed by [
PREVIOUS
1 or [
NEXT
1 when needed)
While the particular event is displayed, delete the event from the timetable by pressing:
[ DELETE 1
[ ENTER 1
The instrument will respond, DELETED.
To modify the time associated with an event, first display the event by pressing:
\mmM
I TABLE I
(followed by [
To modify the time press: I
TIME
PREVIOUS
1 or [
NEXT
1 when needed)
I followed by the new time value, [ ENTER 1
The instrument will respond, MODIFIED.
For example, to change VALVE 1 ON
1.00 is displayed) the key sequence is:
1.00 to
VALVE 1 ON
2.00, (while VALVE 1 ON
The result is valve 1 will turn on at 2 minutes rather than 1 minute.
Making a Run
7-23
Contents
Chapter 8: Storing and Loading HP 5890 SERIES II Setpoints
Storing GC Setpoints
Loading GC Setpoints
8-1
8-2
8
Storing and Loading
HP 5890 Series II Setpoints
Up to three sets of GC setpoints may be stored in the HP 5890 Series II (hereafter referred to
as HP 5890). GC setpoints include any entry made through the HP 5890 keyboard. These sets
of GC setpoints are stored in storage registers designated as 1, 2, or 3.
Storing GC Setpoints
To store a set of setpoints currently in the HP 5890 into a storage register, use the following key
sequence:
register 1, 2, or 3
\
STORE 1
P [ J
[ ENTER
Storing Setpoints
8-1
Loading GC Setpoints
WARNING
BE CAREFUL WHEN LOADING GC SETPOINTS FROM A STORAGE
REGISTER. STORED SETPOINTS MAYTURN DETECTORS ON OR SET
HIGH OVEN TEMPERATURES WHICH, WITHOUT PROPER GAS FLOW,
COULD DAMAGE A DETECTOR OR COLUMN.
To load a set of setpoints already stored in one of the storage registers, the key sequence is:
register 1, 2, or 3
\
Loading setpoints replaces all the setpoints currently defined in the HP 5890 with the setpoints
in the storage register selected.
As a guide to recording GC setpoints stored in storage registers, the following pages may be
photocopied and used to record a list of setpoints before they are stored. Keep these lists for
your records when preparing to load setpoints.
Storing Setpoints
8-2
Storage Setpoint Log
INJATEMP
PET A TEMP
PET B TEMP
EQUIBTIME
OVEN MAX
[
OVEN TEMP
f
INIT VALUE
INITTIME
[
FINAL VALUE
FINAL TIME
FINAL VALUE
FINAL TIME
j
FINAL VALUE
FINAL TIME
RANGE 2 t ( )
PURGE/VALVE
PURGEA^ALVE
[
PURGE/VALVE
C
PURGE^/ALVE
PURGEA^ALVE
PURGE/VALVE
[
CRYOPARAM
COLCOMP1
[
COLCOMP2
[
FLOW PARAM
TCP SENS
J
Storing Setpoints
8-3
Storage Setpoint Log (continued)
[ OVEN TRACK 1
C
INJATEMP
[
INIT VALUE
[
INITTIME
[ ON \ | OFF
[ FINAL VALUE
[ FINAL VALUE
FINAL TIME
[
INJ A PRES
1
[
INIT VALUE
J
[
INITTIME
[ FINAL VALUE
1
[ FINAL VALUE J
I
A
[
1
[
FINAL TIME
|
A
FINAL VALUE
[
FINAL VALUE
J
FINAL TIME
[
FINAL TIME
1
FINAL TIME
L
INJ B PRES
1
[
INIT VALUE
1
[
INITTIME
1
Storing Setpoints
8-4
1
[ FINAL VALUE
FINAL TIME
[
1
|~~B"
FINAL T I M E J
f~B~
Storage Setpoint Log (continued)
Time Table Events:
Storing Setpoints
8-5
Contents
Chapter 9:
Controlling Valves
Turning Valves On/Off Manually
9-2
9
Controlling Valves
Control of up to four valves (designated as valve 1, 2, 3, and 4) may be accomplished in two
ways.
• During a run (see chapter 7, "Turning Valves On/Off During a Run")
• Manually through keyboard entry as described in this chapter
Note: If the valve is already in the position where a command instructs it to switch, no action
will occur.
The following figure illustrates some examples of the HP 5890 SERIES II (hereafter referred to
as HP 5890) alphanumeric display for listing current valve status or verifying the timed events
table to switch the valve during a run.
ACTUAL
SETPOINT
ACTUAL
SETPOINT
VALVE 1 ON
VALVE 1 OFF
I
Typical Valve Status Displays
Controlling Valves
9-1
Turning Valves On/Off Manually
The designated channels (1, 2, 3, or 4) are determined solely by the wiring connections to the
valve box. However, often valves will be located as shown in the figure below.
Top View
Valve
Locations
i
Front
Valve Locations
Controlling Valves
9-2
i
Valves may be switched from the keyboard at any time by pressing the key sequence:
Valve 1,2, 3 o r 4
rojn or G^D
\
C
PURGE/VALVE
J
( 2 I
I"ON"1
[ ENTER
To display the current status of a valve, press:
Valve 1,2, 3 or 4
\
C
PURGE/VALVE
If the HP 5890 display is already displaying the appropriate addressed valve, the operator need
only press the ON or OFF key to activate or relax the displayed valve.
A valve resets automatically at the end of each run. If the last switching mispositioned the valve
for the start of the next run, the valve position will reset at the end of the run.
Controlling Valves
9-3
Contents
Chapter 10: Using Electronic Pressure Control
What Is Electronic Pressure Control?
Using Electronic Pressure Control with Inlets (EPC)
Using Electronic Pressure Control with Detectors (Auxiliary EPC)
Safety Shutdown for Electronic Pressure Control
What Happens During Electronic Pressure Control Safety Shutdown?
Summary Table of Safety Shutdown
Setting Inlet Pressure Using Electronic Pressure Control
Zeroing the Pressure
Setting Constant Flow Mode
Setting Inlet Pressure Programs
Checking Inlet Pressure Programs
Setting Pressure Using Auxiliary Electronic Pressure Control
How Do I Access Auxiliary Electronic Pressure Control?
Setting Constant Detector Pressure
Setting Detector Pressure Programs
Checking Detector Pressure Programs
Suggested Ranges for Operating Auxiliary Electronic Pressure Control
Using Electronic Pressure Control to Control Gas Row
Accessing the Row Parameter Displays
Selecting the Gas Type
Setting the Column Diameter
Setting the Column Length
Using Vacuum Compensation Mode
Using Constant Flow Mode for Inlets
Setting Mass Flow Rate for Inlets
Setting Inlet Flow Programs
Setting the Average Linear Velocity
Understanding Average Linear Velocity
Calculating Outlet Flow
Setting the Average Linear Velocity
Determining the Corrected Column Length
Packed Column Considerations
Capillary Column Considerations
Optimizing Splitless Injection Using
Electronic Pressure Control
Operating the Gas Saver Application for the Split/Splitless Inlet
10-1
10-2
10-2
10-4
10-4
10-5
10-6
10-6
10-8
10-9
10-11
10-12
10-13
10-14
10-15
10-16
10-17
10-22
10-24
10-25
10-26
10-26
10-27
10-28
10-29
10-30
10-32
10-32
10-33
10-33
10-34
10-34
10-34
10-36
10-38
What Is the Gas Saver Application?
What Are the Required Settings for Operation? . . . . .
How Is the Gas Saver Application Configured?
How Does the Gas Saver Application Operate?
Zero the Channel
Enter the Carrier Gas Pressure
Enter the Column Parameters
Set the System to Operating Conditions
Set the System to Off-Hour Conditions
Recommended Row Rates for Inlet Systems
Using the Gas Saver Application
Additional Benefits of the Gas Saver Application
Using the External Sampler Interface
Which Configuration Should I Use?
Using the External Sampler Interface with an Inlet as a Heated Zone
Special Considerations
Using Valve Options
Which Valves Work Best with Auxiliary Electronic Pressure Control?
10-38
10-38
10-39
10-40
10-40
10-41
10-41
10-42
10-42
10-43
10-43
10-44
10-44
10-54
10-54
10-57
10-60
10
Using Electronic Pressure Control
What Is Electronic Pressure Control?
The electronic pressure control (EPC) option for the HP 5890 Series II Plus GC allows you to
control the inlet and auxiliary gases from the keyboard.
You access the inlet and auxiliary detector gases by pressing one of the key sequences shown in
the following table. The keys you press depend on how your GC is configured. For example, if
auxiliary channel C is programmed to control the makeup gas for detector A, you would access
the auxiliary EPC channel C to access control of that gas.
To Access:
Press:
Injector A pressure
— EPC Controls Inlet Gas
INJB
TEMP
Injector B pressure
Auxiliary EPC channel C
Auxiliary EPC channel D
COL
COMP1
Auxiliary EPC
Controls Detector Gas
Auxiliary EPC channel E
Auxiliary EPC channel F
With EPC, inlet and detector pressures can be either constant or programmed. The following
sections describe the benefits of using EPC for inlets and detectors.
Using Electronic Pressure Control 10-1
Using Electronic Pressure Control with Inlets (EPC)
EPC of inlets provides very accurate and precise control of column head pressure, typically
resulting in retention time reproducibility of better than 0.02% RSD when no column effects
are present. With EPC, you can set constant pressure and pressure programs through the
keyboard. Inlet pressures can also be set to maintain a desired column flow rate when the
column parameters have been entered.
Using Electronic Pressure Control with Detectors (Auxiliary EPC)
Auxiliary EPC allows you to control detector gases electronically. With auxiliary EPC, you can
set constant pressure and pressure programs through the keyboard. Auxiliary EPC is provided
by the combination of new, electronically controlled flow modules for gases and the PC board
capability to control those modules.
Auxiliary EPC of detector gases allows you to program the makeup gas to optimize a detector's
performance. With auxiliary EPC, you can control:
• All detector gases, including makeup, carrier, and fuel gases
•
Gas flow to an external sampling device, such as a purge and trap or headspace system
•
Gas flow through the split vent of a split/splitless inlet, which can save gas and optimize the
operation of the inlet (see "Operating the Gas Saver for the Split/Splitless Inlet" in this
chapter)
The following table shows the multiple uses of EPC for inlets and auxiliary EPC for detectors:
Uses for EPC and Auxiliary EPC
EPC
Auxiliary EPC
Head Space
•
•
Purge and Trap
•
•
Gas Saver
Thermal Desorption
•
•
•
Note: All HP 5890 instruments built before July 1,1990, will display the message Change EPC
ROM when used with EPC. When this occurs, contact a Hewlett-Packard service representative
to upgrade and install the new ROM.
Using Electronic Pressure Control 10-2
For additional EPC information, see the HP application note "Analysis of Oxygenates in
Gasoline, Including ETBE and TAME, Using Dual-Channel Electronic Pressure Control,"
HP Application Note 228-174, publication no. (43) 5091-4701E.
This chapter is divided into several sections, including general EPC instructions, optimization
information for inlets, and optimization information for detectors. Specifically, this chapter
provides operating and optimization information for the following EPC systems:
• Split/splitless capillary inlet with EPC
• Septum purged packed Inlet with EPC
• Auxiliary EPC of detector gases
• Auxiliary EPC with Gas Saver for the split/splitless inlet
• Auxiliary EPC with external sampling devices
Operating information for the programmable cool on-column inlet is provided in a separate
manual included with the manual set. The following table describes the features that are
available for specific uses and applications of EPC:
Features of Electronic Pressure Control
Pressure
Constant Pressure Constant Set Mass Flow** SetAvg.
Vacuum
Controlled Function Pressure Programs Flow Mode Flow Rate Programs Linear Velocity Comp.*
Split/Splitless Cap.
Inlet (Carrier Gas)
•
•
•
•
•
•
•
Septum PP
Inlet (Carrier Gas)
•
•
•
•
•
•
•
Programmable
Cool On-Column Inlet
•
•
•
•
•
•
•
Auxiliary EPC
(Detector Gas)
•
•
Auxiliary EPC
(Gas Saver)
•
•
Auxiliary EPC
(General Purpose)
•
•
^Auxiliary inlet channel will calculate the vacuum compensation.
**You enter the required pressures.
Note: Constant flow mode is recommended for use with 530 [i capillary columns. For packed
columns, you must calibrate for each individual column to correct for different column lengths
and possible settling of the column packing.
Using Electronic Pressure Control 10-3
Safety Shutdown for Electronic Pressure Control
Systems equipped with EPC have a safety shutdown feature to prevent gas leaks from creating
a safety hazard. The safety shutdown feature is designed to prevent an explosive concentration
of hydrogen carrier gas from accumulating in the GC oven if a column breaks.
Back pressure regulated inlet systems (split/splitless capillary inlet) with EPC cannot detect a
column leak, however, because a column leak would occur before the gas reaches the EPC
valve. These systems limit the leak rate into the oven using the total flow controller. Under
these conditions, hydrogen diffusion out of the oven is fast enough to keep hydrogen concentration below the 4.1% lower explosion limit.
What Happens During Electronic Pressure Control Safety Shutdown?
If the system cannot reach a pressure setpoint, the system beeps. After about 2 minutes, the
beeping stops and the following message appears on the display:
ACTUAL
SETPOINT
: SAFETY SHUTDOWN
The system shuts down by entering a pressure setpoint of zero for the affected channel, turning
off all heated zones, and locking the keyboard. The table on the following page summarizes the
safety shutdown.
Using Electronic Pressure Control 10-4
Summary Table of Safety Shutdown
Summary Table of Safety Shutdown
What channels can shut down?
The system can shut down all inlet and auxiliary channels.
When does the system start beeping?
The beeps start 10 seconds after the pressure falls below
0.1 psi of setpoint.
What is the frequency of the beeping?
The system beeps at 10,40, 60, 70, 79, 87, 94,100,105,
109,112,114,115,116,117,118,119, and 120 seconds.
When does the system stop beeping?
The beeps stop 120 seconds after the system falls short of
the setpoint pressure. The actual safety shutdown begins.
What happens after the safety
shutdown occurs?
1. The keyboard locks.
2. All heated zones are turned off.
3. The oven fan is turned off.
4. The GC display shows the shutdown message.
5. The other pressure setpoints do not change.
6. The setpoint of the affected EPC channel is set to 0.0.
Note: These safety shutdown procedures apply to EPC boards with a mainboard ROM of
HP part number 05890-80310 or higher.
Using Electronic Pressure Control 10-5
Setting Inlet Pressure Using Electronic Pressure Control
If your GC is equipped with EPC, you can set constant pressure or create a pressure program
with multiple ramps. The following procedures will show you how to:
•
Zero the pressure sensor in all channels and depressurize the system
• Set and maintain a constant pressure
• Set a pressure program using one or two ramps
• Check your pressure program
For more information on setting inlet pressures, see chapter 4, "Setting Inlet Pressure."
Zeroing the Pressure
The EPC system is zeroed before shipping, but you should check it periodically, especially when
ambient laboratory conditions change dramatically. Zero the instrument 30 to 60 minutes after
the system has heated up to allow for electronic drift.
To zero an EPC channel:
1. Turn off the inlet and detector gases. With zero pressure, remove the inlet septa and
depressurize the inlet.
Note: If the detector gas valves are closed, you will not be able to depressurize the system.
Note: When EPC is part of a GC-MS system, zero the pressure when either the MS pump
is off or the column is not connected to the inlet. Otherwise, the vacuum pump will lead to
miscalibration.
2. Use the steps below to zero channels A through F:
• To zero channel A:
a. Press: P&^igil [ INJATEMP~1 1 o 1 I
1 I o I ( ENTER 1 Sets the inlet A pressure to 0.0
Allow enough time for the column to completely depressurize.
b. Press: M l
1 2 | [ ENTER 1
va\ue
[ ENTER 1
where value is the zero offset value shown on the GC display labeled "actual."
Using Electronic Pressure Control 10-6
To zero channel B:
a. Press: EiisMi
[
INJ B TEMP ~"1
|
O
| I • 1 1 o I [ ENTER 1 Sets the inlet B pressure to 0.0
Allow enough time for the column to depressurize completely.
I 3 \ I ENTER \ value ( ENTER 1
b. Press: l i i S I
where value is the zero offset value shown on the GC display labeled "actual."
To zero channel C:
a. Press: &£§$i&8fr I
A
) [ o \ [ • \ 1 o 1 [ ENTER \
Sets channel C pressure to 0.0
Allow enough time for the system to depressurize completely.
where value is the zero offset value shown on the GC display labeled "actual."
To zero channel D:
a. Press: ll;iii$i& 1 B 1 1 ° 1 1
\ 1 ° I [ ENTER 1 Sets channel D pressure to 0.0
Allow enough time for the system to depressurize completely.
where value is the zero offset value shown on the GC display labeled "actual."
To zero channel E:
a. Press: l£8$i&;il [
COLCOMPI
1 | o \ [ • \ [ o |[
ENTER
1 Sets channel E pressure to 0.0
Allow enough time for the system to depressurize completely.
b. Press: fesa®^;^ I
6
1 I ENTER 1 value \ ENTER 1
where value is the zero offset value shown on the GC display labeled "actual."
To zero channel F:
a. Press: E&gia&i-I [
COL COMP2~~1
1 o 1 1 • I 1 ° I 1 ENTER"! Sets channel F pressure to 0.0
Allow enough time for the system to depressurize completely.
b. Press: l&l&$i£ift
t
7
1 [ ENTER 1 value [ ENTER |
where value is the zero offset value shown on the GC display labeled "actual."
Using Electronic Pressure Control 10-7
Setting Constant Flow Mode
While using constant flow mode, the pressure will change if the oven temperature changes to
keep the flow constant. When you select constant flow, you can set an initial pressure (at oven
initial temperature) and the GC maintains the initial flow throughout the run by adjusting
pressure continuously and automatically. This example shows how to set the inlet B pressure at
10 psi.
1. Use the following steps to turn on the constant flow mode:
a. Press: Eiggff&gil ( FLOW \ to access the flow parameters display.
b. Continue to press ( FL0W 1 until you see the constant flow display.
SETPOINT
ACTUAL
EPf>8 CONST f LOW OFF
to turn the constant flow mode on.
c. Press:
2. Press: l i M & f l
I
WPPB
3.
Press:
[
INJBTEMP
J
1i I I o I
ACTUAL
SETPOINT
10.0
10.0
INITTIME
5 \
ACTUAL
BMNlTTfME
[
Sets the inlet B pressure to 10 psi
[ENTER
The GC display looks like this
o \
[ ENTER
Sets the initial time to 650 minutes (max.)
SETPOINT
650,00
The GC display looks like this
Inlet B at Constant Pressure
20 psi
-
15 psi
-
10 psi
Opsi
I
0
1
4
i
5
Minutes
r
6
10
Note: Inlet B will stay at 10 psi until the oven temperature changes. Then the pressure will
increase to keep the flow constant.
Using Electronic Pressure Control 10-8
Setting Inlet Pressure Programs
The run time of the analysis is determined by the oven temperature program. If the inlet
pressure program is shorter than the oven temperature program, the inlet pressure does not
remain at the last value but goes into constant flow mode for the remainder of the run. If the
oven temperature is changing, then the pressure will also change. To prevent a pressure
program from going into constant flow mode, set the pressure program longer than the oven
temperature program.
The following procedure shows how to create a pressure program with three pressure ramps for
inlet B.
1. Turn the constant flow mode off.
Note: For more information on setting constant flow mode, see "Using Constant Mass Flow
Mode for Inlets" later in this chapter.
2. Use the following steps to program the first pressure ramp:
The first pressure ramp starts at 10 psi for 1 minute, then ramps at 5 psi/min to 20 psi and
remains there for 2 minutes.
a. Press:
[
b.
Press:
[
c.
Press:
f
d.
Press:
C FINAL VALUE
e.
Press:
C FINAL TIME
INJBPRES
INITTIME
1
[
INIT VALUE
I
f i
Sets inlet B pressure to 10 psi
Sets the initial time at 1 minute
RATE
Sets the ramp rate at 5 psi/min
Sets the final pressure at 20 psi
1
[ 2
Sets the final time at 2 minutes
3. Use the following steps to program the second pressure ramp:
The second pressure ramp starts at 20 psi and ramps at 2 psi/min to 26 psi. It remains at
26 psi for 2 minutes.
RATE
a. Press:
I
b.
Press:
f FINAL VALUE
Sets the second final pressure at 26 psi
c.
Press:
t
Sets the second final time at 2 minutes
FINAL TIME
Sets the second ramp rate at 2 psi/min
Using Electronic Pressure Control 10-9
4. Use the following steps to program the third pressure ramp:
The third pressure ramp starts at 26 psi and ramps at 4 psi/min to 30 psi. It remains at 30 psi
for 2 minutes.
a. Press: ( RATE
Sets the third ramp rate at 4 psi/min
b.
Press:
[ FINAL VALUE 1
[B
c.
Press:
C FINAL TIME
[ B \
1
Sets the third final pressure at 30 psi
|
2 |
[ ENTER 1
Sets the third final time at 2 minutes
The following graph shows the entire three-ramp pressure program.
Inlet B with 3 Pressure Ramps
Opsi
0
1
1
I
2
1
3
i
4
1
5
r
6
7
Minutes
Using Electronic Pressure Control 10-10
9
10
11
12
13
Checking Inlet Pressure Programs
1. Display the pressure program by pressing any pressure program key followed by [ ENTER 1.
2. Press [ ENTER 1 successively to scroll through and view the pressure program.
Note: The oven program determines the run time of the analysis. If the inlet pressure program
is shorter than the oven temperature program, the inlet pressure goes into constant flow mode
for the remainder of the run. To prevent this, make sure that the inlet pressure program is
equal to or longer than the oven program.
Pressure Program
End of
Pressure
Program
Final
Value
i—i
Pressure
f\
\
J
Rate
Init
Value
/
/
Rate A
1 Final
^,.— —
\ Value
Init
Time
End of
Oven
Program
Final
Time
Constant
Flow Mode
Run Time
Using Electronic Pressure Control 10-11
Setting Pressure Using Auxiliary Electronic Pressure Control
Auxiliary EPC is generally used for applications other than the control of carrier gas to the
column. The auxiliary channels (labeled C through F) do not use the pressure versus flow
calculations that the inlet channels have. Only pressure setpoints and programs are entered,
with flow values determined from the calibration curves established.
For applications such as detector gas control, where the restriction is provided mainly by a flow
restrictor in the detector block, the calibration curves are described by the following equation:
F = kxP M
Note: This is the equation used by the HP 3365 ChemStation for pressure versus flow
calculations with the auxiliary EPC channels. Values for the constants k and M are displayed on
the auxiliary pressure programs screen of the ChemStation when the calculations are carried
out. For term definitions, see your ChemStation manual.
Using Electronic Pressure Control 10-12
How Do I Access Auxiliary Electronic Pressure Control?
To access the auxiliary EPC channels, use the following keys at the GC keyboard:
Press:
To Access:
Auxiliary EPC channel C
Auxiliary EPC channel D
Auxiliary EPC channel E
Auxiliary EPC channel F
The pressure that you program at the keyboard is the pressure the HP
3365 ChemStation uses in its calculations. When operating under low
pressure, such as 15 psi, be sure to program the same pressure (15 psi)
at the keyboard. If the rate entered at the keyboard is higher, the
ChemStation will base its calculations on that rate, which may not be the
accurate flow through your system.
Using Electronic Pressure Control 10-13
Setting Constant Detector Pressure
This example shows how to set the auxiliary EPC channel C pressure at 10 psi. For additional
operating information, see chapter 5, "Operating Detector Systems."
1. Press:
Sets auxiliary EPC channel C pressure to 10 psi
HPPC
2. Press: [
INITTIME
I
ACTUAL
SE7POINT
10.0
10.0
|T
ACTUAL
C: INITTIME
The GC display looks like this
Sets the initial time to 650 minutes (max.)
SETPOINT
650,00
The GC display looks like this
Auxiliary EPC Channel C al Constant Pressure
20 psi
-
15 psi
-
10 psi
Opsi
0
1
i
4
i
5
Minutes
Using Electronic Pressure Control 10-14
r
6
10
Setting Detector Pressure Programs
The following procedure shows how to create a pressure program for auxiliary EPC channel C
with three pressure ramps. For additional operating information, see chapter 5, "Operating
Detector Systems."
1. Use the following steps to program the first pressure ramp:
The first pressure ramp starts at 10 psi for 1 minute, then ramps at 5 psi/min to 20 psi and
remains there for 2 minutes.
a. Press:
;
INIT VALUE
1
[
1 I I o I ( ENTER ) Sets auxiliary EPC channel C initial
pressure to 10 psi
b.
Press: [
c. P r e s s : (
1
INIT TIME
Press:
t
Sets the initial time at 1 minute
RATE
Sets the ramp rate at 5 psi/min
d. Press: L FINAL VALUE 1
e.
1 t ENTER 1
FINAL TIME
1
[2
1 2 \
Sets the final pressure at 20 psi
( ENTER
Sets the final time at 2 minutes
2. Use the following steps to program the second pressure ramp:
The second pressure ramp starts at 20 psi and ramps at 2 psi/min to 26 psi. It remains at
26 psi for 2 minutes.
a. Press:
Sets the second ramp rate at 2 psi/min
b. Press: [ FINAL VALUE 1
c.
Press:
t
FINAL TIME
1
6 I
( T
[ A \
[ 2 \
[ENTER
ENTER
Sets the second final pressure at 26 psi
Sete the second final time at 2 minutes
Using Electronic Pressure Control 10-15
3. Use the following steps to program the third pressure ramp:
The third pressure ramp starts at 26 psi and ramps at 4 psi/min to 30 psi. It remains at 30 psi
for 2 minutes.
a . Press: I
RATE
Sets the third ramp rate at 4 psi/min
b. Press:
[ FINAL VALUE 1
[ B
c. Press:
[ FINAL TIME I
[ B |
Sets the third final pressure at 30 psi
| 2 | [ ENTER 1
Sets the third final time at 2 minutes
The following graph shows the entire three-ramp pressure program.
Auxiliary EPC Channel C with Three Pressure Ramps
Ramp.1
Ramp
2
30 psi
25 psi
Ramp
3
-
4 psi/mm
20 psi
2 psi / min
/
15 psi
-
/
10 psi
5 psi / min
/
-
I
0 psi
0
1
I
2
i
3
I
4
I
5
I
I
I
I
I
I
6
7
Minutes
I
8
9
10
11
12 13
Checking Detector Pressure Programs
To check your pressure program, press [ ENTER 1 successively to scroll through and view the
program immediately after setting it.
Using Electronic Pressure Control 10-16
Suggested Ranges for Operating Auxiliary Electronic Pressure Control
The following graphs show the ranges that Hewlett-Packard suggests to optimize the operation
of auxiliary EPC for detectors. The graphs show the flow restrictor you will need (the restrictors
are identified by colored dots) and the corresponding pressure versus flow relationship. Use the
table that most closely corresponds to the gas type you will use in your analysis.
Using Electronic Pressure Control 10-17
Auxiliary EPC Restrictor Kit
19234-60600 Green and Brown Dot
Computed nominal values at ambient temperature of 21 °C and pressure of 14.56 psia
Pressure
(kPa)
Pressure
(psig)
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
10
20
30
40
50
60
70
80
90
100
Helium Flow Nitrogen Flow Hydrogen
(ml/min)
(ml/min)
Flow (ml/min)
20
45
76
111
150
190
232
275
321
22
50
87
131
182
239
300
366
437
513
42
99
170
251
344
442
549
666
786
901
Air Flow
(ml/min)
Argon/Meth
Flow (ml/min)
21
45
76
110
148
188
229
273
318
363
19
40
65
95
128
164
202
242
282
324
Flow Restrictor Data
19234-60600
700
Hydrogen/
/
600
/
Helium
500
Flow
ml/min
/
/
m
^Hitrogen^ Air
Arg/Meth
/
300
200
100
/
20
^
40
60
Pressure, psig
Using Electronic Pressure Control 10-18
80
100
120
Auxiliary EPC Restrictor Kit
19231-60610 Brown Dot
Computed nominal values at ambient temperature of 21 °C and pressure of V 156 psia
Pressure
(kPa)
Pressure
(psig)
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
10
20
30
40
50
60
70
80
90
100
Helium Flow Nitrogen Flow Hydrogen
(ml/min)
(ml/min)
Flow (ml/min)
76
174
302
457
634
838
1063
1310
1580
1873
61
161
279
418
571
740
915
1101
1297
Air Flow
(ml/min)
Argon/Meth
Flow (ml/min)
65
157
273
410
561
726
900
1084
1278
1470
55
134
235
352
485
627
782
945
1110
1270
150
344
596
896
1243
1634
2035
2456
2918
Flow Restrictor Data
19231-60610
1200
i
Helium/
/
/
1OOO
Hydrogen,
800
/
Flow
ml/min 6oo
/ Nitrogen -
/
/ / .
/
/
^
7y
/
/
(V
/
^Arg/Meth
V/
/
400
/
200
A
20
40
60
80
100
120
Pressure, psig
Using Electronic Pressure Control 10-19
Auxiliary EPC Restrictor Kit
19243-60540 Green and Red Dot
Computed nominal values at ambient temperature of 21 °C andpressure of 14.56 psia
Pressure
(kPa)
Pressure
(psig)
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
10
20
30
40
50
60
70
80
90
100
Helium Flow Nitrogen Flow Hydrogen
(ml/min)
(ml/min)
Flow (ml/min)
7.2
17
29
44
61
80
100
124
150
178
14.7
35
59
88
122
159
200
243
290
339
6.4
15
26
39
53
69
86
104
123
143
Air Flow
(ml/min)
Argon/Meth
Flow (ml/min)
6.2
15
25
38
52
67
84
101
120
139
5.7
13
22
33
46
59
74
89
106
123
Flow Restrictor Data
19243-60540
250
200
Helium
Nitrogen
150
Flow
ml/min
1OO
50
60
Pressure, psig
Using Electronic Pressure Control 10-20
80
100
120
Auxiliary EPC Restrictor Kit
19234-60660 Blue Dot
Computed nominal values at ambient temperature of 21 °C and pressure of V 1.56 psia
Pressure
(kPa)
Pressure
(psig)
Helium Flow Nitrogen Flow Hydrogen
(ml/min)
Flow (ml/min)
(ml/min)
Air Flow
(ml/min)
Argon/Meth
Flow (ml/min)
1.0
2.1
3.6
5.4
7.4
9.7
12.3
15.2
18.3
22.0
0.9
2.0
3.4
5.0
7.0
9.2
11.7
14.5
17.5
20.6
0.9
1.9
3.2
4.8
6.4
8.4
10.5
12.9
15.5
18.4
10
20
30
40
50
60
70
80
90
100
69.0
137.9
206.8
275.8
344.7
413.7
482.6
551.6
620.5
689.5
1.3
2.7
4.4
6.4
8.8
11.5
14.5
17.7
21.2
24.9
2.0
4.6
8.1
12.3
16.9
22.2
27.9
34.5
41.5
49.7
Flow Restrictor Data
19234-60660
25
Helium
Nitrogen
Air
/ Hydrogen
/A
20
Arg/Meth
Flow
ml/min
/
/
15
/
/
10
/
/,
1
20
40
60
80
100
120
Pressure, psig
Using Electronic Pressure Control 10-21
Using Electronic Pressure Control to Control Gas Flow
With EPC, you can also control flow by setting the pressure. The following procedures will show
you how to:
• Access the flow parameter displays
• Select the gas type
• Set the column diameter
•
Set the column length
•
Use the vacuum compensation mode
• Set constant mode for inlets
• Set mass flow rate for inlets
Pressure is the parameter controlled and measured with the EPC system; however, the
corresponding column outlet flow rate and average linear velocity are also calculated and
displayed. Entries can be made in terms of velocity from which the system calculates the
required pressure and enters this setpoint.
The following example shows the relationship between pressure and flow for EPC systems. In
the first table, pressure is constant and the flow changes with temperature. In the second table,
flow is constant and pressure changes with temperature.
Using Electronic Pressure Control 10-22
Constant Pressure with Changing Flow
50
Temperature (° C)
3.6
Flow (ml/min)
100
2.8
150
2.3
200
1.9
250
1.6
300
1. 3
Pressure (psi)
15
15
15
15
15
15
Linear Velocity (cm/sec)
51. 1
46. 3
42.4
39.1
36.2
33.7
Constant Flow with Changing Pressure
Temperature (° C)
Flow (ml/min)
50
3.6
100
3.6
150
3.6
200
3.6
250
300
3.6
3.6
Pressure (psi)
15
18
21.9
24
27. 1
30.2
Linear Velocity (cm/sec)
51. 1
55. 1
58.3
60.9
63. 1
65.0
Using Electronic Pressure Control 10-23
Accessing the Flow Parameter Displays
Use the following steps to access and scroll through the GC flow parameters displays.
1. Press: i;i;%8&lil [ FLOW 1 to access the flow parameters displays.
2. Continue to press: t FL0W 1 to scroll through the flow parameter displays. The displays may
be in a different sequence depending on your configuration.
Flow Parameter Displays
ACTUAL
SETPOINT
Use this display to turn the constant
flow mode on or off.
CONST PLOW OFF
ACTUAL
HI
He
SPPB
ACTUAL
WPPB
0:
Split
0
Use this display to turn the vacuum
compensation mode on or off.
SETPOINT
Use this display to set the column diameter.
SETPOINT
Column Lon 10,00 M
ACTUAL
Use this display to change the gas type.
SETPOINT
Column Did .530 mm
ACTUAL
0:
1
VAC CONK* OFF
ACTUAL
0:
SETPOINT
Use this display to set the column length.
SETPOINT
MI/MIn
Using Electronic Pressure Control 10-24
Use this display to set the mass flow rate.
Selecting the Gas Type
You will need to select or verify the gas type you are using for EPC applications. To select the
gas type:
1. Press: [.^..H ( FL0W 1 to access the flow parameters display.
2. Continue to press: [ FLOW 1 until the gas type appears on the GC display.
ACTUAL
SETPOINT
m
The GC display now looks like this.
3. Press the number corresponding to the gas type you want to use. The chart below lists the
gas types available:
Gas Type
Helium
Nitrogen
Hydrogen
Argon/Methane
The number and gas you select will appear under the "setpoint" column on the GC display:
ACTUAL
EPPB
SETPOINT
^2
[2f
I
The GC display now looks like this.
Using Electronic Pressure Control 10-25
Setting the Column Diameter
To set the column diameter:
1. Press: i&ail&il ( FLOW 1 to access the flow parameters display.
2. Continue to press: [ FLOW 1 until you see the column diameter display.
ACTUAL
8:
Column Ola
SETPOINT
<XXX
The GC display looks like this.
3. Enter the column diameter in \i (such as 200 \i, 320 \i, 530 (x). The example below shows the
column diameter for a 530 \i column.
Press:
[ o I
ENTER
ACTUAL
B:
Column 01a
|
Sets the column diameter to 530 fi.
SETPOINT
,530 mm
The GC display looks like this.
Setting the Column Length
If you do not know the exact column length or if you are using a packed column, follow the
steps described in "Determining the Corrected Column Length" later in this chapter. To set the
known column length in meters:
1. Press: t^iS&aiil I FLOW 1 to access the flow parameters display.
2. Continue to press: I FLOW 1 until you see the column length display.
ACTUAL
B:
SETPOINT
Column t e n XX.XXM
The GC display looks like this.
3. Enter the column length in meters.
Sets the column length to 25 meters.
ACTUAL
Column
SETPOINT
2&WU
Using Electronic Pressure Control 10-26
The GC display looks like this.
Using Vacuum Compensation Mode
Use vacuum compensation mode when you are using a mass spectrometer to correct for the
column outlet pressure. Using the vacuum compensation mode ensures that the constant flow
mode, calculated column flow, and average linear velocity are correct.
1. Press: I sold ...I [ FL0W ) to access the flow parameters display.
2. Continue to press: f FL0W ) until you see the vacuum compensation display.
8 VACCOMP
OFF
The GC display looks like this.
3. Use one of the following steps to turn the vacuum compensation mode on or off:
a. Press: f ON ) to turn vacuum compensation mode on.
After you select vacuum compensation, set the desired pressure. For more information
on setting the inlet pressure, see "Setting Inlet Pressure Using Electronic Pressure
Control" earlier in this chapter.
b. Press: [ OFF ) to turn vacuum compensation mode off.
Using Electronic Pressure Control 10-27
Using Constant Flow Mode for Inlets
Before setting the constant flow mode for inlets, you must first select the gas type. See
"Selecting the Gas Type" earlier in this chapter for more information.
Note: The initial pressure changes when you turn the constant flow mode on or off. Enter the
desired initial pressure after selecting constant flow mode. Also, make sure that the oven is
equilibrated to the initial temperature. If you set the initial pressure before the oven reaches
the initial oven temperature, the flow will be incorrect.
To use constant mass flow mode:
1. Press: &;i;ii^ii&fl [ FLOW 1 to access the flow parameters display.
2. Continue to press: [ FLOW 1 until you see the constant flow display.
ACTUAL
SETPOINT
EPP8 CONST FLOW OFF
3. Use one of the following steps to turn the constant flow mode on or off:
a. Press: 1 ON 1 to turn the constant flow mode on.
When you select on, you can set an initial pressure (at oven initial temperature) and the
GC maintains the initial flow throughout the run by adjusting pressure continuously and
automatically.
b. Press: [ OFF 1 to turn the constant flow mode off.
You must select off if you want to create independent pressure programs.
Using Electronic Pressure Control 10-28
Setting Mass Flow Rate for Inlets
When a pressure is set, the mass flow rate is displayed. Entering a new mass flow value sets a
new pressure automatically to produce the flow value entered.
1. Enter the correct gas type, column diameter, and column length. For more information on
setting the correct column parameters, see the appropriate sections earlier in this chapter.
2. Use the following steps to set the inlet B mass flow rate to 10 ml/min:
a. Press: C CLEAR ) .
b. Continue to press: I FL0W ) until you see the mass flow control display.
ACTUAL
COLUMN B
c. Press: I 1 )
-000
[ o)
SETPOINT
mJ/mlrt
The GC display looks like this.
[ ENTER ) to set the inlet B flow to 10 ml/min.
Note: Inlet B pressure will change to the value needed to produce a mass flow of
10 ml/min.
Using Electronic Pressure Control 10-29
Setting Inlet Flow Programs
You can use EPC to set flow programs indirectly by setting an inlet pressure program. The
following example shows how to obtain the pressure values necessary to set a pressure program
that results in the desired flow programs.
1. Enter the correct gas type, column diameter, and column length. For more information on
setting the correct column parameters, see the appropriate sections earlier in this chapter.
1. Press: 1 CLEAR I .
2. Continue to press: I FL0W I until you see the mass flow control display.
ACTUAL
COLUMN B
3. Press: I
4
.XXX
SETPOINT
mt/min
The GC display looks like this.
1 I ENTER 1 to set the inlet B initial flow to 4 ml/min.
ACTUAL
COLUMN B
4. Press: H
EPP B
4*0
C
SETPOINT
ml/mln
The GC display looks like this.
INJ B TEMP
ACTUAL
SETPOINT
10,0
10,0
The GC display looks like this.
This will be injector B pressure initial value.
5. Press: I FLOW I repeatedly until you see the mass flow control display.
ACTUAL
COLUMN B
4.0
SETPOINT
ml/mini
Using Electronic Pressure Control 10-30
The GC display looks like this.
6. Press:
ENTER
1 to set the inlet B flow to 7 ml/min.
ACTUAL
COLUMN B
7. Press:
7,0
ml/mlo
The GC display looks like this.
INJ B TEMP
ACTUAL
iPP B
SETPOINT
14,3
SETPOINT
The GC display looks like this. The value
shown will be the inlet pressure setting
needed to obtain the flow you entered.
Use the pressure values obtained from this procedure for setting a pressure program. Enter the
initial time, ramp rate, and final time as part of setting the pressure program (see "Setting
Pressure Programs" earlier in this chapter). You will also need to change the oven temperature
if it will change during the pressure program.
Using Electronic Pressure Control 10-31
Setting the Average Linear Velocity
You can use EPC to set the calculated average linear velocity for inlets. For example, when you
set a pressure, the average linear velocity is displayed (while monitoring the average linear
velocity). The following sections will show you how to:
•
Understand average linear velocity
• Calculate the outlet flow
• Set the average linear velocity
• Calculate the outlet linear velocity
• Calculate the actual average linear velocity
Understanding Average Linear Velocity
The average linear velocity is calculated and measured at oven temperature, rather than at
ambient temperature. It is an average value because velocity varies continually along the length
of the column (due to the pressure drop and the compressibility of the carrier gas).
To compare experimental values with those displayed by the system, measure the outlet flow
and compare it to the calculated outlet flow. Then measure the average linear velocity and
compare it to the velocity displayed. You need to consider the corrections for both temperature
and compressibility if you use the average linear velocity (unretained peak time) measurements
to calculate flow. You can calculate an approximate value for flow without correcting for
compressibility, but it may differ significantly from the flow value displayed by the system as the
pressure drop increases. A more detailed discussion of these calculations and pressure versus
flow relationships is given in appendix A, "Pressure versus Flow Relationships for Inlet and
Auxiliary Electronic Pressure Control."
Using Electronic Pressure Control 10-32
Calculating Outlet Flow
Outlet flow is the gas flow out of the column. It is measured in ml/min and corresponds to the
measurements made with a flow meter at the detector outlet. The gas is measured at ambient
conditions; however, the outlet flow displayed is calculated using 25 °C and 1 atmosphere
pressure (14.7 psi) as reference conditions.
All flow calculations are based on the ideal gas law.
Ideal Gas Law
PV = nRT
where
T = temperature in K
P = absolute pressure
Setting the Average Linear Velocity
Use the following steps to set the approximate column B average linear velocity to 100 cm/sec.
1. Enter the correct gas type, column diameter, and column length. For more information on
setting the correct column parameters, see the appropriate sections earlier in this chapter.
2. Use the following steps to set the column B average linear velocity to 100 cm/sec:
a. Press: i CLEAR I .
b. Continue to press: I FL0W J until you see the average linear velocity display.
ACTUAL
COLUMN B
SETPOINT
Cm/Sec
The GC display looks like this.
The value displayed (97.5 cm/sec) is the computed average linear velocity (u) for the
correct pressure, temperature, and gas type.
c. Press:
Sets inlet B linear velocity to 100 cm/sec.
Note: Inlet B pressure will change to a value needed to produce 100 cm/sec at the current
oven temperature. Inlet B flow also corresponds to that pressure.
Using Electronic Pressure Control 10-33
Determining the Corrected Column Length
Packed Column Considerations
• Calculations for the pressure versus flow relationship with EPC apply to flow through open
tubular columns.
Measure flow versus pressure to determine the relationship for a packed column and to
check for changes as a column is used.
•
Operating pressure may reach the 100 psi limit for longer columns or higher temperatures.
•
EPC offers many advantages over mass flow controllers, including:
- Precision and reproducibility of setpoints
- Rapid adjustment to change in settings during downstream operation
- Pressure programming capability for reduced run times
To set or display the mass column flow for a packed column, you must first calculate the
corrected column length and diameter for an equivalent open tubular column.
Capillary Column Considerations
Although column specifications show the nominal length of the column, not all columns are
manufactured exactly to the nominal specifications. Also, previously used columns are shorter
than their specifications if the ends were cut off to remove contaminants.
To compensate for both packed and capillary column considerations, use the following
procedure to determine the corrected column length and diameter.
Using Electronic Pressure Control 10-34
Note: Before setting the mass flow rate, enter the correct gas type, column diameter, and
column length. For more information on setting the correct column parameters, see the
appropriate sections earlier in this chapter.
1. Use the following steps to set the column B average linear velocity:
a. Press: ( CLEAR ) .
b. Press: IFL0W J repeatedly until the display reads:
ACTUAL
COLUMN B
97x5
SETPOINT
Cm/Sec
The value displayed (97.5 cm/sec) is the computed average linear velocity (u) for the
estimated length (10 M) column.
2. Inject an unretained component into the GC and determine its retention time in minutes.
This is to Actual in the following equation.
3. Use the following formula to calculate the corrected column length:
L corrected
C
t o Actual X
u
where:
1.67
^ corrected
= corrected column length in meters
t
= retention time of unretained component in minutes
0
Actual
u
= average linear velocity in cm/sec
1.67
= (cm to M) 60 min corrections
4. Press: &;&i<i%iil [ FL0W ) to access the flow parameters display.
5. Continue to press: [ FL0W 1 until you see the column length display.
ACTUAL
S:
Column U n XX.XXM
SETPOINT
The GC display looks like this.
6. Enter the value calculated from the above formula as the corrected column length.
You can check the flow through the column by turning off the detector gases and measuring
the flow using a bubble flow meter and the GC stopwatch feature. See chapter 4, "Using the
Internal Stopwatch" for more details.
Using Electronic Pressure Control 10-35
Optimizing Splitless Injection Using
Electronic Pressure Control
The inlet carrier gas pressure at the time of injection can affect the transfer of sample to the
column dramatically. With low inlet carrier gas pressure, the column flow rate is slower so the
sample stays in the inlet longer. Because of this, the sample has more time to expand. In
addition, low inlet carrier gas pressure results in lower inlet pressure and a larger sample
expansion volume. Conversely, higher flows (or higher pressures) at the time of injection cause
the sample to be swept into the column more rapidly, thus reducing the expansion volume.
Because the inlet pressure can be programmed up or down, it is possible to initiate a run
with a high flow rate and then program the flow downward to a value that is optimal for the
chromatographic separation.
Splitless injection volumes are usually limited to 1 to 2 \x\ of sample, but this is highly
dependent upon factors such as the inlet temperature, column flow rate, solvent molecular
weight, solvent boiling point, liner volume, column type, and retention gap use. With
larger injections, poor sample transfer can result in sample losses and molecular weight
discrimination.
A slightly modified pressure programming technique is appropriate for GC-MS systems.
The program starts at a low initial pressure, then ramps up at the beginning of the GC run, and
ramps down again after the sample has been transferred to the column.
An example of rapid pressure programming for a GC-MS system is shown on the following
page.
Using Electronic Pressure Control 10-36
Example Setpoints of Rapid Pressure Programming
Rapid Pressure Program
GC-MS
Constant Flow
Constant Pressure
Init Pres
Init Time
Rate
Final Pres
Final Time
Rate A
Final Pres A
Final Time
10
0
99
40
0.25
99
10
0
Rate
Init
Pres
Init
Time
Single-Ramp Oven Temperature Program
Final
Value.
Init Value
Init Time
Rate
Final Value
Final Time
Init
Value
100
2
10
200
1
Run Time
Using Electronic Pressure Control 10-37
Operating the Gas Saver Application for the
Split/Splitless Inlet
What Is the Gas Saver Application?
The gas saver application is one use of the auxiliary EPC system. It allows you to control
the split vent flow of a split/splitless inlet by controlling supply pressure to the inlet. By
controlling the pressure, you can reduce the total flow rate during nonproductive run times and
laboratory off-hours, which will reduce your GC operating costs. The gas saver is particularly
beneficial for users of expensive carrier gas and for capillary inlet systems used with high split
flows. When properly programmed for a capillary inlet system, constant column head pressure
and column flow rate are maintained while the excess split flow is reduced.
What Are the Required Settings for Operation?
When you operate the gas saver, you must set the auxiliary pressure at least 5 to 10 psi greater
than the inlet head pressure to ensure that column pressure and flow are maintained. To
determine the minimum auxiliary setting, detect the maximum pressure of the programmed run
and add 5 to 10 psi. If you are not using constant flow mode, the column pressure drop
increases and the column flow decreases. If you are using constant flow mode, the pressure will
increase during temperature programming. In general, the operating constraints for the gas
saver application are as follows:
•
Operate at least 5 to 10 psi above column head pressure (some minimal split vent flow is
required).
•
Operate at least 10 psi above the supply line pressure (or as maintained by the system).
• Use the GC displays and warnings when configuring.
Using Electronic Pressure Control 10-38
How Is the Gas Saver Application Configured?
Auxiliary EPC Module
Split/Splitless Inlet,
Back-Pressure Regulation with EPC
Pressure
Transducer
To EPC Board,
Channel C
~1
l
— -n
Flow
FilterRestrictor
Split/
Splitless Inlet
Septum
Purge Line
Septum Purge
Regulator
Septum
Purge Vent
Flow
Restrictor
Supply
Gas Flow
Electronic
Pressure
Control
Valve
Pressure Mass Flow
Transducer Controller
To EPC
Board,
Channel
AorB
To Detector
Electronic
Pressure
Control
Valve
Using Electronic Pressure Control 10-39
How Does the Gas Saver Application Operate?
When an EPC module is used for gas supply to the split/splitless inlet (gas saver
configuration), restriction is due mainly to the mass flow controller. You can vary the
restriction by changing the setting of the mass flow controller.
To operate in gas saver mode, you need to enter the gas type, column length, column diameter,
column pressure, and split flow rate. You will also need to calibrate the flow versus the
pressure, set the mass flow controller to the desired range, and determine the column head
pressure. Be sure that all the hardware is installed properly and that all gases are plumbed.
Use this procedure to determine the settings that will yield the most gas savings for your
system:
Zero the Channel
1. Check your system for leaks.
2. Zero your channel if ambient conditions have changed significantly:
a. Make sure that all heated zones are cool.
b. Set the auxiliary and inlet pressures to zero.
c. Remove the septum nut to depressurize the system completely. The example below
shows the display for auxiliary EPC channel C.
Note: Setting the inlet pressure to 0.0 may noty depressurize the channel completel. You
may also need to bleed off at the 1/8-in Swagelok fitting.
d. Press:
E : M&*fl 1 A 1 I ° 1 I • 1 I o 1 1ENTER 1
ACTUAL
SETPOINT
10»0
0x0
Sets the channel C pressure to 0.0.
The GC display looks like this.
where 10 is the zero offset value labeled "actual" on the GC display.
Using Electronic Pressure Control 10-40
Enter the Carrier Gas Pressure
1. Enter the carrier gas supply pressure at the keyboard. A typical pressure is 50 to 60 psi.
For example:
a. Press:
TO&3&&
1
C:
A
1 I
5
1 [ o )
[ ENTER 1
ACTUAL
SETPOINT
50*0
50*0
Sets the channel C pressure to 50.0.
The GC display looks like this.
2. Turn the mass flow controller on the front of the flow panels until you measure
80 to 100 ml/min (or the desired flow) with the bubble flow meter.
Note: You must wait 1 to 2 minutes after changing pressure or mass flow controller settings
to allow the system to stabilize before measuring flows or making an injection.
Enter the Column Parameters
1. At the keyboard, press: [&§®fo£]| [ FLOW | to access the flow parameters table.
2. Press: I FLOW 1 to scroll through the table. Enter your values for the following:
• Constant flow (on or off)
•
Gas type
• Vacuum compensation (on or off)
• Column diameter
• Column length
• Split flow
For more information on setting these parameters, see the appropriate sections earlier in
this chapter.
3. To verify the column flow, measure the flow out of the detector with a bubble flow meter.
Using Electronic Pressure Control 10-41
Set the System to Operating Conditions
Use the flow restrictor tables described in "Setting Pressure Using Auxiliary Electronic Pressure
Control" earlier in this chapter to select the makeup gas pressure that will yield the flow you
need. For example, the following steps describe how to set the pressure to get 30 ml/min
makeup gas flow.
1. Set the inlet pressure to 10 psi (if it is not set already).
2. Set the makeup gas at the keyboard to get to approximately 30 ml/min.
3. Start to heat any heated zones that are not already heated.
WARNING
HEAT THE DETECTOR BEFORE YOU CONTINUE.
4. If you did not select constant flow, verify the flows after the zones reach their desired
temperatures.
5. After the system reaches equilibrium, check and record the final pressure at the maximum
operating temperature.
Note: Record the final pressure so that you know what value to set for the reduced gas saver
pressure, and then observe the pressure at the maximum operating temperature. If you want
a higher temperature than listed in the operating manual, realize what that pressure will be
when you reset it.
Set the System to Off-Hour Conditions
If the final column pressure is 50 psi, set the carrier gas pressure to 65 psi. During off-hours,
you can program the carrier gas down.
1. Program the desired oven temperature.
2. Set all detector and inlet flows and pressures to the desired levels.
3. Set the carrier gas pressure to a value 15 psi higher than the column head pressure.
Using Electronic Pressure Control 10-42
Recommended Flow Rates for Inlet Systems
Using the Gas Saver Application
For a capillary split/splitless injection port, a combined flow rate out of the split vent and the
purge vent of approximately 5—10 ml/min is recommended.
Additional Benefits of the Gas Saver Application
If desired, the makeup gas flow can also be reduced using the gas saver mode during off-hours
to increase total gas savings. Plumb the gas saver outlet line into the detector manifold inlet
fitting for makeup gas. Then set it using the same procedure as for a carrier gas.
With a capillary inlet, the gas saver can also be used as a quick, convenient way to set split ratio.
The graphs below show examples:
Split Injection
High Flow just during
Sample Splitting Period
(plus Oven Cooldown Cycle)
Oven
Cooldown
Period
I
I
\
I
5
67
8
GC Run Time (in Minutes)
I
10
11
12
Splitless Injection
CO
0
1
5
6
7
8
GC Run Time (in Minutes)
Using Electronic Pressure Control 10-43
13
Using the External Sampler Interface
The external sampler interface kit (HP part number 19245-60990) enables you to use EPC with
a sampling device other than a standard HP inlet. The conventional interfacing of external
sampling devices is not possible when EPC inlets are used. The external sampler kit provides
the hardware and diagrams for installing the kit onto forward-pressure controlled inlets
(programmable cool on-column and purged packed). The kit also contains hardware for limited
use of the back pressure-regulated split/splitless inlet. This hardware allows the system to sense
the pressure at a different location inside the HP pneumatic system.
Which Configuration Should I Use?
The external sampler interface is configured differently depending on the type of inlet you use.
You will select one of several typical configurations of the external sampler interface depending
on how you use your inlet. Use the following tables to determine the configuration you need.
The diagrams shown in this section include the most commonly configured systems.
External Sampler Interface Kit
Inlet Use
Auxiliary Module
External Inlet
•
•
HP inlet used as a thermal zone
•
•
HP inlet used for injection
•
Forward-Pressure Regulation
Inlet Use
Front End Sampler for Purged
Packed and On-Column Inlets
Back-Pressure Regulation
Front End Sampler Interface for
Split/Splitless Inlets
External Interface
•
•
HP inlet used for sample
introduction
•
•
HP inlet not used for
sample introduction
•
•
Using Electronic Pressure Control 10-44
External Sampler Interface Configuration Decision Tree
Use Aux
EPC module
See configuration
BPR
split/splitless
iniet
ill you use this
inlet for sample
introduction?
Is it an FPR
(purged packed
oron-column)
inlet?
> - No
ill you use this
inlet for sample
introduction?
See
configuration 6
Is the inlet use
as a thermal zone
only (purge and
trap)?
See
ill sample be
introduced through
the septum?
configurations
2 and 4
No interface
kit needed
See
configuration 7
No
sample be
introduced through
the septum?
Sample introduced
through the carrier
line
See configuration 5
No
Yes
Sample introduced
through the carrier
line
See configuration 1
See configuration 3
Using Electronic Pressure Control 10-45
Configuration 1: External Sampler Interface to HP Inlet with FPR
Forward-pressure regulation for the septum-purged packed inlet (EPC used with open
tubular columns). External sampler interface (needle through septum) to HP inlet with
forward-pressure control. A static headspace sampler can be interfaced in this way.
EPC
Board
Heated
Interface
External
Sampler
~l
-F-
Pressure
Transducer
I Adapter
I Fitting
Carrier
Septum Purge Regulator
(with Brass M8 Plug)
Septum
Septum Purge
Gas
Flow
Electronic
Pressure
Control Valve
New Pressure Sensor
Line to the Transducer
Using Electronic Pressure Control 10-46
External Sampler
Direct to Column
Interface
Flow
Restrictor
Capped
Septa
Purge
(if
required)
Configuration 2: External Sampler Interface to Column or to HP Inlet with FPR
Forward-pressure regulation for the on-column inlet and the septum-purged packed inlet
(EPC used with open tubular columns). To External Sampler direct column interface or to HP
inlet. Use the HP inlet with forward EPC.
Heated
Transfer Line External
Sampler
Pressure
Transducer
Septum Purge
Regulator (with Septum
Brass M8 Plug) Purge Vent
Carrier
Gas
Flow
Direct to
Column
Interface
in Injection
Port Location
Electronic
Pressure
Control Valve
Flow
/N
Restrictor |
Capped
Septa Purge
(if required)
New Pressure Sensor
Line to the Transducer
To Detector
The position of the three-way valve directs the EPC flow to the external sampler or to the HP
inlet. This diagram shows the EPC flow directed to the external device.
Using Electronic Pressure Control 10-47
Configuration 3: EPC to External Sampler to HP Inlet with FPR
Forward-pressure regulation for the on-column inlet and the septum-purged packed inlet (EPC used
with open tubular columns). From HP EPC pneumatics to external sampler and return to HP inlet. This
configuration should not be used with compounds that have a retention index greater than 400-450.
EPC
Board
External
Sampler
Pressure
Transducer
<r
V
Carrier
Gas
Flow
Septum Purge Regulator Septum
(with Brass M8 Plug)
Purge Vent
r
Septum Purge
Flow
Restrictor
Electronic
Pressure
Control Valve
Column
Using Electronic Pressure Control 10-48
Capped
Septa
Purge
Configuration 4: EPC to External Sampler
Forward-pressure regulation for the on-column inlet and the septum-purged packed inlet
(EPC used with open-tubular columns). To external sampler only. The HP pneumatics are
used. The HP inlet is not functional.
Inlet not Connected to
pneumatics (blocked with
1/8-inSwagelokcaps)
Heated
Transfer Line
Direct to
Column
Interface
in Injection F i o w
Port Location
Column
Pressure
Transducer
Septum Purge
Regulator (with
Brass M8 Plug)
Septum
Purge
Vent
Flow
Capped
Restrictor Septa
Purge
(if
required)
Electronic
Pressure
Control Valve
New Pressure Sensor
Line to the Transducer
To Detector
Using Electronic Pressure Control 10-49
Configuration 5: Back Pressure Regulated EPC with Inlet
Back-pressure regulation for the spliVsplitless inlet. The external sampler is placed in the HP
spliVsplitless capillary inlet flow system (in series). The external sampler transfer line was interfaced (cutting 1/16-in. od tubing is required) close to inlet carrier in line. Septa purge is
capped to prevent sample losses. The pressure sensing takes place just before the EPC valve.
Pressure
Transducer
Septum Purge
Regulator (capped)
Carrier
Gas
Flow
Flow
Septum
Restrictor Purge
Vent
Solenoid Valve ( ca PPed)|-
External Sampler placed in
Series with HP Split/Splitless
capillary inlet. A static
headspace sampler would
interface to an EPC split inlet
in this way.
Electronic
Pressure
Control
Valve
V
To Detector
Using Electronic Pressure Control 10-50
Split
Vent
\
I
M8 x M8 union
with Post Drawn
Weldment Tube for
Pressure Sensing
Configuration 6: Back Pressure Regulated EPC with No Inlet
Back-pressure regulation for the split/splitless inlet. External sampler using the HP inlet
back-pressure regulation of column. HP inlet not used. The external sampler has its
own direct column interface in the unused inlet opening.
Pressure
Transducer
Split/Splitless Inlet
Septum Purge
septum Purge
Regulator (capped) Vent (capped)
Septum Purge Line i
31
1
Carrier
Gas
Flow
HOW
|
Restrictor
|
i
i
Solenoid Valve
External Sampler
Direct Column
Interface
Column
Electronic
Pressure
Control
Valve
Split
Vent
U EPC
1 Board
I
M8 x M8 union
with Post Drawn
Weldment Tube for
Pressure Sensing
To Detector
Using Electronic Pressure Control 10-51
Configuration 7: Forward Pressure Regulated EPC with Inlet as Thermal Zone
Forward-pressure regulation for the septum-purged packed inlet (EPC used with
open tubular columns). External sampler interface direct to column with HP inlet forward
EPC. HP inlet used only as heated transfer and support of direct column interface device.
EPC
Board
Heated
Interface
Pressure
Transducer
Adapter
Fitting
Carrier
Gas
Flow
Septum Purge Regulator pNPnp
(with Brass M8 Plug)
vent
Septum Purge
Electronic
Pressure
Control Valve
New Pressure Sensor
Line to the Transducer
Using Electronic Pressure Control 10-52
External Sampler
direct to column
interface
mmwmz
Flow
Restrictor
Capped
Septa
Purge
(if
required)
Configuration 8: EPC with Auxiliary EPC Module
Aux EPC Module
(as Carrier Source)
Sampling Device
HP 5890 GC
For more information on using auxiliary EPC, see the headspace configuration in "Using Valve
Options" later in this chapter. For further information, see "Applications of Auxiliary
Electronic Pressure Control in Gas Chromatography," HP application note 228-202, HP
publication number (43) 5091-5013E.
Using Electronic Pressure Control 10-53
Using the External Sampler Interface with an Inlet as a Heated Zone
The external sampler device introduces a slight pressure drop over the system. To compensate
for this pressure drop, measure the actual flow with a bubble flow meter to determine the
additional pressure necessary during the run. For example, measure the flow at the column
outlet, or use an unretained peak to determine the average linear velocity. The pressure setting
will probably be somewhat higher than would be used by the column alone.
Special Considerations
If you are using an HP 19395A headspace sampler with a needle interface to the inlet, replace
the septum nut with the black septum nut with the wide aperture before using it.
For easier access to the external sampler interface, try to place the three-way flow diverter
valve so it is reached easily through the side door of the GC.
Some devices go into a timed desorbtion cycle that increases the pressure drop through the
system, consequently reducing the flow rates. To compensate for the increased pressure drop,
program a pressure ramp at the beginning of the start cycle. For example, ramp the pressure
from 16 psi to 35 psi at 99 psi/min. Then program the pressure down to 16 psi for the duration
of the analysis.
Whenever an external device is placed in series with an EPC inlet system, some of the direct
flow displays will be incorrect because we do not know what the total pressure drops are
relative to just the column (such as column id and length). In this case, ignore the display and
measure the actual flows. If the external device switched valves, multiple columns, or traps
during a run, then the flows may also change. You may want to compensate for these situations
in your pressure programs.
Using Electronic Pressure Control 10-54
The standard forward-pressure configuration is shown below.
Forward-Pressure Regulation for the On-Column Inlet and the
Septum-Purged Packed Inlet (EPC Used with Open-Tubular Columns)
EPC
Board
r
Programmable Cool
On-Column Inlet
Pressure
Transducer
e
Septum Purge
Regulator
Septum
Purge
Vent
Carrier
Gas
•
Septum Purge
Flow
Flow
Restrictor
Electronic Pressure
Control Valve
Column
To Detector
Using Electronic Pressure Control 10-55
The standard back-pressure configuration is shown below.
Back-Pressure Regulation for the Split/Splitless Inlet
Pressure
Transducer
I
Septum
Purge
Regulator
Split/Splitless Inlet
Septum Purge Line
Carrier
Gas
Flow
Septum |
Purge
Vent
:
Mass Flow
Controller
N.c.
Split Line
N.O.
COM.
Column
To Detector
Electronic
Pressure
Control
Valve
s |jt
P
Vent
Using Electronic Pressure Control 10-56
U
^
low
Restrictor
Solenoid Valve
EPC
Board
Using Valve Options
The valve options described in this section demonstrate several applications of the auxiliary
EPC system. Hewlett-Packard supplies 17 standard plumbing configurations for the HP 5890.
These configurations may be ordered through the HP 18900F Valve Ordering Guide,
HP part number 5091-4240E.
This section describes advanced auxiliary EPC valving applications that will require some
method development time from the user. In general, all HP valves are compatible with auxiliary
EPC. However, some valve options may require additional method development time. For
some configurations, such as a packed-column refinery gas analyzer that operates isothermally,
an auxiliary EPC module can be used in constant pressure mode as easily as the standard
mechanical pneumatics. With packed-column valve applications, be sure to check the flows with
a bubble flow meter every time you change the system pressure.
If you run your system only in constant flow or constant pressure mode, without pressure
programs, then an auxiliary EPC module may be just as effective as a manual flow controller for
your applications. However, most operations become easier to automate once you are using
EPC. In fact, EPC should give faster response to changes in the back pressure of the column
and better repeatability of known retention times. When constant flow mode is used with
packed columns, actual flow may increase or decrease with temperature programming. It is best
to calibrate the flow at the initial and final oven temperatures, and then use a two-point
calibration with pressure programming.
The following diagram shows a common 10-port valve configuration plumbed with an EPC
split/splitless inlet and one general-purpose auxiliary EPC module. This configuration is used
for the analysis of oxygenates in gasoline.
Using Electronic Pressure Control 10-57
10-Port Valve Configuration with Two Channels of EPC
56-cm Micropacked TCEP
Carrier
Gas Flow
00005000
Split/Splitless
Inlet with EPC
Mass Flow
Controller
30 m x 0.53 mm x 2.6 m HP-1
00000001
Channel A
S2
Supply
Gas Flow
DET
Aux
EPC
Module
ChannelC
'•
Adjustable
Restrictor
Vent
Using Electronic Pressure Control 10-58
Headspace Sampling Systems Product
Vent
Carrier
Gas Flow
Aux
EPC
Module
r\
S2
Supply
Gas Flow
Aux
EPC
Module
Sample
Loop
f
Needle
toGC
Headspace Vial
EPC can be applied to headspace sampling. The six-port valve configuration in the figure above
shows the application of two general-purpose auxiliary EPC modules. One module is used for
carrier gas flow, and the other module is used for precise vial pressurization.
Using Electronic Pressure Control 10-59
Which Valves Work Best with Auxiliary Electronic Pressure Control?
Almost all HP valves are compatible with auxiliary EPC, and many of the standard
configurations offer additional system benefits. For example, using valve options for specific
applications can help you maintain better reproducibility, reduce ambient temperature
sensitivity, and rapidly change the flow rate. Using valves with auxiliary EPC also contributes to
easier setup and simplified automation. In addition, auxiliary EPC valves make it easier to
change run times and to reduce analysis time.
Valve configurations such as Options 205 and 401 can also be used with EPC. If pressure
programming is used, you may need to change the pressure program whenever you change the
valve timing. Failing to change the pressure program will produce incorrect results.
Precolumn
Vent
2nd
Carrier
(EPC)
Column
Detector
OFF
-•H—•
ON
Options 205 and 235 backflush precolumn
Using Electronic Pressure Control 10-60
A common application has Option 401 interfaced to a capillary Split inlet. The system uses an
EPC Split/Splitless inlet (main carrier) and one general-purpose auxiliary EPC module for
control of the second carrier source. The interface between the capillary inlet and the valve is
Option 901.
Split/Splitless EPC Injection Port B
Split Vent
Capil
lumn 2
Detector
2
Packed
Precolumn
Injection
PortB
Carrier
Sample
In
Sample
Out
Aux Carrier
(Aux EPC)
OFF
Valve 1
Option 401. Detector 1—FID, Detector 2—TCD
Using Electronic Pressure Control 10-61
A
Appendix
Pressure versus Flow Relationships for Inlet and Auxiliary
Electronic Pressure Control
While pressure is the parameter controlled and measured with the EPC system, the
corresponding column outlet flow rate and average linear velocity are also calculated and
displayed on the keypad. Entries can also be made in terms of either flow or velocity, from
which the system calculates the required pressure and enters this setpoint.
It is important to understand how pressure, flow, and linear velocity are related so that the
displayed values can be compared with each other and with the correct experimental measurements. This section includes a summary of some of the basic equations for flow through open
tubular columns and the calculations that are carried out by the HP 5890 Series II GC and
HP 3365 ChemStation systems. Some of the terms and units used throughout this section are
shown below.
Terms and Units Used in This Section
F
Column outlet flow, ml/min
V
Average linear velocity, cm/sec
L
Column length, cm
r
Column inner radius, cm
t
Retention time, seconds
T
Column (oven) temperature, K (°C + 273)
11
Carrier gas viscosity at temperature T, poise
Pi
Inlet pressure, absolute
Po
Outlet pressure, absolute; zero if vacuum compensation specified
Tref
Reference temperature; 25 °C = 298 K
Pref
Reference pressure; 1 atm = 14.7 psi = 1.01325 x 106 dynes/cm2
Tref/T
298 / 323 = 0.923
Column
25 m x 0.32 mm, Helium carrier
Appendix A-1
Outlet Flow
Column outlet flow can be calculated from Equation 1:
F=
60:ir4
).2 _ p 2
16T)L
Pref
Eql
Since the gas volume depends on both temperature and pressure, it is expressed here under
reference conditions, Tref and Pref. Flows displayed by the 5890 are based on reference
conditions of 25 °C and 1 atmosphere pressure, for comparison with experimental values
measured under ambient conditions with a flow meter at the outlet of the detector.
Average Linear Velocity
Flow cannot always be measured directly at the detector outlet, as in work with a mass
spectrometer or at very low flow rates. An alternative is to measure the elution time for an
unretained peak and calculate the average linear velocity for gas flowing through the column.
This value is determined at oven temperature T.
v =
Eq2
t
The average linear velocity can also be calculated from pressure, temperature, and column
parameters according to Equation 3, as was done for outlet flow using Equation 1.
(Temperature does not appear separately, but is included in the viscosity term in this equation.)
3r2
(Pi 2 - Po 2 ) 2
32r)L
(Pii 3 "
v =
Eq3
This is the calculation used for the velocity value displayed by the HP 5890. It is calculated at
oven temperature, corresponding with experimental measurements from elution time of an
unretained peak (equation 2).
Appendix A-2
Calculating Flow from Average Linear Velocity
Combining equations 1 and 3 gives an equation that can be used to calculate flow from average
linear velocity.
F = 60:ir2
T
Tref I f
. JL
2
3Pref
(pi3 ~ po3)
2
Eq4
2
(Pi - Po )
Terms for both temperature and pressure appear in this equation. The ratio Tref/T corrects for
the difference in temperature (ambient versus oven) at which flow and velocity were calculated.
The pressure term is related to effects of the gradient from inlet to outlet pressure. Because the
carrier gas is compressible, linear velocity varies along the length of the column, depending on
the pressure at each point. Retention time measurements reflect the average linear velocity v,
but the pressure-gradient term must be included to calculate flow at the outlet.
Column flow is often approximated from measurements of unretained peak time according to
equation 5, without including these corrections (see chapter 4, "Setting Inlet System Flow
Rates" earlier in this manual).
F • 60jir2v
Eq 5
This can be a good approximation, when the pressure drop is small and temperature is near
Tref. The compressibility correction becomes increasingly important as the pressure drop
increases, however, and flow values approximated using equation 5 may differ significantly
from those calculated by the system according to equation 4.
The examples below show how the two flow calculations compare for one column under
different sets of operating conditions. In these examples, temperature has been held constant
to illustrate the effect of changes in the compressibility factor. It can be seen from the
equations, however, that changes in the temperature ratio will also affect the overall result and
comparison between calculations.
Appendix A-3
Keyboard Displays
Example
Inlet Pressure
Flow (ml/min)
Velocity (cm/sec)
1
4.6 psig (19.3 psia)
1.00
19.3
2
8.3 psig (23.0 psia)
2.00
34.5
3
14.3 psig (29.0 psia)
4.00
58.4
Example 1—Inlet Pressure 4.6 psig
1. Calculating flow from the average linear velocity using equation 4:
F = 60 (3.14) (0.016)2 (0.923)
2
3 (14.7)
(19.3)3 - (14.7)(19.3)2 - (14.7)2
F = (0.0482) (0.923) [1.164] (19.3) = 1.00
2. Calculating flow from the average linear velocity using the approximation in Equation 5:
F a 60(3.14)(0.016)2v
F a (0.0482) (19.3) = 0.93
Example 2—Inlet Pressure 8.3 psig
1. Calculating flow from the average linear velocity using Equation 4:
F = 60(3.14)(0.016)2 (0.923)
(23.0)3 - (14.7)-
F = (0.0482) (0.923) [13.03] (34.5) = 2.00
2. Calculating flow from the average linear velocity using the approximation in Equation 5:
F a 60(3.14)(0.016)2~v
F a (0.0482) (34.5) = 1.66
Appendix A-4
Example 3—Inlet Pressure 14.3 psig
1. Calculating flow from the average linear velocity using equation 4:
F = 60 (3.14) (0.016)2
f
(0.923) I
2
3{UJ)
(29.0)3 - (14.7)3'
(29.0)2 _ (14>7) 2
F = (0.0482) (0.923) [1.540] (58.4) = 4.00
2. Calculating flow from the average linear velocity using the approximation in equation 5:
F* 60 (3.14) (0.016) 2 v
F * (0.0482) (58.4) = 2.82
References
More detailed discussions on pressure versus flow relationships in capillary GC can be found in
many general references; two are listed here.
1. W.E. Harris and H.W Habgood, Programmed Temperature Gas Chromatography, Wiley, New
York, 1966.
2. J.C. Giddings, Unified Separation Science, Wiley, New York, 1991.
Appendix A-5
Index
Adapters, bubble flow meter, 4-4
Assigning a signal, 6-2
Attenuation
on/off, output signals, 6-12
output signals, 6-9
Auxiliary zones
suggested pressure ranges, 10-17
temperature control, 3-15
with EPC, 10-2
Average linear velocity, 10-32, 10-33, A-2
B
Bead
conditioning, 5-44
contamination, 5-53
power setting, 5-45
preserving lifetime, 5-54
Bubble flow meter, 4-2
adapters, 4-4
Capillary columns
corrected length, 10-34
flows for FID, 5-21
flows for NPD, 5-49
flows for TCD, 5-31
flows with ECD, 5-63
flows with FPD, 5-71
installation in ECD, 2-28
installation in FID, 2-20
installation in FPD, 2-32
installation in NPD, 2-20
installation in packed inlets, 2-12
installation in split/splitless inlets, 2-14
installation in TCD, 2-24
preparation, 2-2
Capillary inlet
flows, 4-9
flows in split mode, 4-11
flows in splitless mode, 4-18
Carrier gas, for TCD, 5-33
Carrier gases, type, 4-25
Column
corrected length, 10-34
diameter, 10-26, 10-41
length, 10-26, 10-41
Column compensation
assigning data, 5-40, 7-12
displaying status, 5-37
making a compensation run, 5-38
message displays, 5-39
single, 5-36
starting a run, 7-10
status display, 7-9
Column installation, 2-1
1/4 in. metal in FID, 2-16
1/4 in. metal in NPD, 2-16
1/8 in. in FID, 2-18
1/8 in. in NPD, 2-18
1/8 in. metal in FPD, 2-30
1/8 in. metal in TCD, 2-22
capillary in capillary inlets, 2-14
capillary in ECD, 2-28
capillary in FID, 2-20
capillary in FPD, 2-32
capillary in NPD, 2-20
capillary in packed inlets, 2-12
capillary in TCD, 2-24
capillary inserts, 2-4
glass columns in ECD, 2-26
glass columns in packed inlet, 2-10
metal columns, 2-8
Column preparation
capillary columns, 2-2
metal columns, 2-6
Compensation, single column, 5-36, 7Constant flow, inlets, 10-28
Cryogenic oven control, 3-6
Daily shutdown, 1-2
Daily startup, 1-2
Detectors
ECD, 5-56
FID, 5-16
FPD, 5-68
NPD, 5-42
TCD, 5-29
nitrogen-phosphorus, 5-42
pressure control, 10-14
pressure programming, 10-15
status, 5-2
temperature control, 3-13, 3-15
temperature display, 3-13
with EPC, 10-2
Display, output signals, 6-5
ECD—Electron Capture Detector
contamination, 5-66
flow rates, 5-60
flows for packed columns, 5-62
flows with capillary columns, 5-63
gases, 5-59
installing capillary columns, 2-28
installing glass columns, 2-26
leak testing, 5-67
operation, 5-56
pressure control, 5-64
radioactive leaks, 5-67
selecting gases, 5-61
temperature effects, 5-59
U.S. owners, 5-57
Electronic pressure control
EPC—Electronic Pressure Control, 10-1
and valves, 10-60
auxiliary pressure control, 10-12
auxiliary zones, 10-2
auxiliary, suggested ranges, 10-17
constant flow mode, 10-8
detectors, 10-2
FID, 5-24
FID makeup gas, 5-27
flow and pressure relationships, A-l
inlets, 10-2
mass flow rate, 10-29
optimizing splitless injection, 10-36
programming inlet flow, 10-30
safety shutdown, 10-4
vacuum compensation mode, 10-27
Equilibration time, 3-5
External sampler interface, 10-44,10-54
FID—Flame Ionization Detector
flows for capillary columns, 5-21
gas flows, 5-19
installing capillary columns, 2-20
installing metal columns, 2-16, 2-18
lighting flame, 5-28
makeup gas control, 5-26
on/off control, 5-27
operation, 5-16
optimizing, 5-16
Flow control
EPC, 10-22
inlet programming, 10-30
Flow ranges, packed inlet, 4-5
Flow rates
bubble meter, 4-2
display, 4-25
measuring, 4-1
outlet, 10-33, A-2
recommended for gas saver, 10-43
Rows
capillary columns with ECD, 5-63
capillary columns with FID, 5-21
capillary columns with FPD, 5-71
capillary inlet, 4-9
capillary split mode, 4-11
capillary splitless mode, 4-18
displays, 10-24
ECD, 5-60
ECD with packed columns, 5-62
EPC constant flow mode, 10-8
FID, 5-19
NPD with capillary columns, 5-49
NPD with packed columns, 5-47
packed columns with FPD, 5-69
stopwatch, 4-27
FPD—Flame Photometric Detector
flows for packed columns, 5-69
flows with capillary columns, 5-71
installing capillary columns, 2-32
installing metal columns, 2-30
lighting the flame, 5-74
on/off control, 5-74
operation, 5-68
pressure control, 5-72
Glass columns
installation in ECD, 2-26
installation in packed inlets, 2-10
H
Heated zones
actual, 3-2
detector temperatures, 3-13
inlet temperatures, 3-13
setpoints, 3-2
I
INET, 6-14, 7-14
start/stop a run, 7-1
Inlet flow control, 4-1
Inlets
constant flow, 10-28
flow rates for gas saver, 10-43
gas saver and capillary inlet, 10-38
mass flow rate, 10-29
pressure control with EPC, 10-6
pressure programming, 10-9
programming flow, 10-30
temperature control, 3-13, 3-15
temperature display, 3-13
with EPC, 10-2
Inserts, split/splitless inlet, 2-4
Installation, checklist, 1-1
G
Installing columns, 2-1
Gas flows, FID, 5-19
Gas saver
operation, 10-38
recommended flows, 10-43
zeroing, 10-40
Leak test, ECD, 5-67
Gas selection, ECD, 5-61
LED, status indicators, 7-2
Gas type, 10-25
Lightening the flame, FPD, 5-74
Gases, ECD, 5-59
Loading setpoints, 8-1, 8-2
Leak testing, ECD, radioactive, 5-67
M
Makeup gas, FID, 5-26
Making a run, 7-1
Mass flow rate, 10-29
Metal columns
installation in FID, 2-16, 2-18
installation in FPD, 2-30
installation in NPD, 2-16, 2-18
installation in packed inlets, 2-8
preparation, 2-6
Output signals
andlNET, 6-14
as timed events, 7-20
assigning, 6-2
attenuation, 6-9
attenuation on/off, 6-12
display or monitor, 6-5
on/off control, 6-8
zeroing, 6-7
Oven
cryogenic operation, 3-6
temperature control, 3-4
temperature control and display, 3-4
temperature programming, 3-8
N
NPD—Nitrogen-Phosphorus Detector
bead lifetime, 5-54
bead power, 5-45
conditioning the bead, 5-44
contamination, 5-53
flows for capillary columns, 5-49
flows for packed columns, 5-47
installing capillary columns, 2-20
installing metal columns, 2-16, 2-18
on/off control, 5-52
operation, 5-42
optimizing, 5-53
On/off control
FID, 5-27
FPD, 5-74
NPD, 5-52
signal attenuation, 6-12
signals, 6-8
TCD, 5-35
valves, 7-18, 9-2
Optimizing
NPD, 5-53
splitless injection, 10-36
Outlet flow, 10-33, A-2
Packed columns
corrected length, 10-34
ECD flows, 5-62
flows for NPD, 5-47
flows for TCD, 5-30
flows with FPD, 5-69
gas flows for FID, 5-19
Packed inlet
flow ranges, 4-5
installing capillary inlets, 2-12
installing glass columns, 2-10
installing metal columns, 2-8
septum purge, 4-6
Polarity inversion, TCD, 5-35, 6-12
Pressure control
auxiliary EPC, 10-12
capillary columns with FPD, 5-72
detector programming, 10-15
detectors, 10-14
ECD, 5-64
EPC, zeroing, 10-6
for FID, 5-24
for FID makeup gas, 5-26
for TCD, 5-32
inlet programming, 10-9
inlets with EPC, 10-6
NPD with capillary columns, 5-50
restrictors, 10-17
Programming
checking inlet pressures, 10-11
detector pressure, 10-15
inlet flow, 10-30
inlet pressure, 10-9
oven temperature, 3-8
Restrictors, 10-17
Run
making, 7-1
start/stop, 7-1
start/stop using INET, 7-1
Safety shutdown, 10-4
Sensitivity, TCD, 5-34, 7-22
Septum purge, 4-6
Setpoints
loading, 8-1, 8-2
storing, 8-1
Shutdown, instrument, 1-2
Signal output, 6-1
Signals
and INET, 6-14
as timed events, 7-20
assigning, 6-2
attenuation, 6-9
attenuation on/off, 6-12
display or monitor, 6-5
on/off control, 6-8
zeroing, 6-7
Split/splitless inlet
gas saver, 10-38
inserts, 2-4
installing capillary columns, 2-14
Splitless injection, optimizing, 10-36
Splitless mode, flows in capillary inlet, 4-18
Start/stop control, run, 7-1
Startup, instrument, 1-2
Status
column compensation, 7-9
LEDs, 7-2
valves, 9-1
Stopwatch, 4-27, 7-6
Storing setpoints, 8-1
TCD—Thermal Conductivity Detector
carrier gas type, 5-33
changing sensitivity, 7-22
flows for capillary columns, 5-31
flows for packed columns, 5-30
installing capillary columns, 2-24
installing metal columns, 2-22
on/off control, 5-35
operation, 5-29
polarity inversion, 5-35, 6-12
pressure control of flow, 5-32
setting sensitivity, 5-34
Temperature, effects on ECD, 5-59
Temperature control
auxiliary zones, 3-15
detectors, 3-15
heated zones, 3-1
oven, 3-4
Temperature limits, 3-3
Single column compensation, 5-36, 7-8
Temperature programming, oven, 3-8
Split mode, flows in capillary inlet, 4-11
Time key, 7-6
Timetable
creating an event, 7-17
events, 7-15
modifying events, 7-23
switching signals, 7-20
valve control, 9-3
V
during a run, 7-18
on/off control, 7-18, 9-2
options, 10-57
yy
WARN:OVEN SHUT OFF, 3-6
Wipe test, ECD, 5-67
Vacuum compensation, 10-27
Valve, status, 9-1
Valve box, 3-16
Valves
and EPC, 10-60
controlling, 9-1
tm
Zeroing
EPC pressure, 10-6
gas saver, 10-40
output signals, 6-7
Programmable Cool On-Column
HP 5890A Series II Plus
Programmable Cool On-Column Inlet
What HEWLETT
l l ' & l PACKARD
Manual Part No.
05890-90300
Edition 9, June 1993
Printed in U.S.A.
Printing History
The information contained in this document may be revised without notice.
Hewlett-Packard makes no warranty of any kind with regard to this
material, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Hewlett-Packard shall not be
liable for errors contained herein or for incidental, or consequential damages
in connection with the furnishing, performance, or use of this material.
No part of this document may be photocopied, reproduced, or translated to
another program language without the prior written consent of
Hewlett-Packard Company.
First edition—June 1989
Second edition—August 1989
Third edition—January 1990
Fourth edition—October 1990
Fifth edition—September 1991
Sixth edition—October 1991
Seventh edition—June 1992
Eighth edition—September 1992
Ninth edition—June 1993
Printed In U.S.A.
Copyright 1993 by Hewlett-Packard Company
All Rights Reserved
Safety Information
The HP 5890A is an IEC (International Electrotechnical Commission) Safety
Class 1 instrument.
This unit has been designed and tested in accordance with recognized safety
standards.
Whenever the safety protection of the HP 5890A has been compromised, disconnect the unit from all power sources and secure the unit against
unintended operation.
Safety Symbols
This manual contains safety information which should be followed by the user
to ensure safe operation.
WARNING
A WARNING CALLS ATTENTION TO ACONDITION OR POSSIBLE
SITUATION THAT COULD CAUSE INJURY TO THE USER.
A Caution calls attention to a condition or possible situation that
could damage or destroy the product or the user's work.
Important User Information for In
Vitro Diagnostic Applications
This is a multipurpose product that may be used for qualitative or quantitative
analyses in many applications. If used in conjunction with proven procedures
(methodology) by a qualified operator, one of these applications may be In
Vitro Diagnostic Procedures.
Generalized instrument performance characteristics and instructions are
included in this manual. Specific In Vitro Diagnostic procedures and methodology remain the choice and the responsibility of the user, and are not
included.
RFI Certification for Federal
Republic of Germany
Manufacturer's Declaration
This is to certify that the equipment HP 5890 SERIES II is in accordance with
the Radio Interference Requirements of Directive FTZ 1046/1984. The
German Bundespost was notified that this equipment was put into circulation,
the right to check the series for compliance with the requirements was granted.
Herstellerbescheinigung
Hiermit wird bescheinigt, da/3 das Gerat/System
HP 5890 SERIES H
in Ubereinstimmung mit den Bestimmungen von Postverfiigung 1046/84
funkentstort ist.
Der Deutschen Bundespost wurde das Inverkehrbringen dieses
Gerates/Systems angezeigt und die Berechtigung zur Uberpriifung der
Serie auf Einhaltung der Bestimmungen eingeraumt.
Contents
Chapter 1 What is the Cool On-Column Inlet?
Features of the HP Programmable Cool On-Column Inlet
....
.
1-3
Chapter 2 Using the Correct Insert, Needle Guide, and Septum
Selecting the Correct Insert
...............................
Changing the Needle Guide and Septum
Selecting the Correct Needle Support Assembly
Using Retention Gaps and Other Precolumns
2-2
2-3
2-4
2-5
Chapter 3 Installing Columns
Preparing a Fused Silica Capillary Column
Checking the Needle-to-Column Size
Installing the Insert
Aligning the Inlet Septum Nut
Installing the Needle into the Syringe Barrel for Automatic Injection
Installing a Fused Silica Capillary Column for Automatic Injection
Checking for Column Installation Problems
3-2
3-3
3-4
3-6
3-7
3-8
3-10
Chapter 4 Setting Inlet Pressure
Selecting the Best Inlet Pressure
Setting Inlet Pressure Using Electronic Pressure Programming
Using the Constant Mass Flow Modes
Setting Mass Flow Rate
Determining the Corrected Column Length
Setting Flow Programs
Setting Average Linear Velocity
Using Vacuum Compensation Mode
Setting Pressure Using Manual Control
4-2
4-4
4-8
4-10
4-12
4-14
4-16
4-17
4-18
Chapter 5 Setting Inlet Temperature
Guidelines for Selecting Inlet Temperature
Setting Inlet Temperature to Follow the Oven Temperature (Oven Track)
Creating an Independent Inlet Temperature Program
Using Cryogenic Cooling
5-1
5-2
5-2
5-3
Chapter 6 Making Injections
Before the Injection
Can I Automate?
Manual Injection Technique with Stainless Steel Needles
Manual Injection Technique with Fused Silica Needles
Replacing the Fused Silica Syringe Needle
Replacing the Universal Syringe Needle
Automatic Injection Considerations
Automated Injection Technique
Performing Automatic Injection onto 250 \xm and 320 \im Columns
Installing the Syringe into the Needle Support Assembly
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-11
Chapter 7 Maintenance and Troubleshooting
Cleaning and Care
Troubleshooting Automatic and Manual Injections
Safety Shutdown
Septum Problems
Syringe Problems
Automatic Sampler Vial Cap Septum Problems
FID Hameout Problems
Peak Broadening and Split Peaks
Proper Configuration
Useful Tools
Index
7-2
7-3
7-6
7-7
7-8
7-9
7-10
7-11
7-13
7-18
1
What Is the Cool On-Column Inlet?
The cool on-column inlet allows the introduction of small volumes of liquid sample into the
column. Manual and automatic injection can be used to introduce sample into columns with
internal diameters (id) of 250 (xm, 320 jim, 530 jim, and larger.
Cool On-Column Inlet
Needle guide for
manual injection
Septum nut
Septum
Needle guide for fused
silica needles
Spring
Duckbill
Insert
Ferrule
Column nut
Column
What is the Cool On-Column Inlet? 1-1
Cool on-column injection is a technique of introducing a sample as a liquid directly onto a
GC column. This lack of prior vaporization offers the following advantages:
•
Eliminates sample discrimination. This is a main source of error in the quantitative
analysis of samples covering a wide range of molecular weights. Inlet-related discrimination does not occur because the liquid is introduced directly onto the cool column.
•
Eliminates sample alteration. Thermally labile components are not exposed to
thermal stress because they begin the chromatographic process at relatively low temperatures. This also reduces decomposition and rearrangement reactions.
•
Provides high analytical precision. If properly performed, on-column injection
provides extremely accurate and precise results.
Cool on-column injection has extended the range of capillary gas chromatography to include
many classes of compounds that until now were difficult, if not impossible, to analyze.
Compared with vaporizing inlets, the cool on-column inlet has some special requirements:
•
Requires relatively clean samples, because the sample is introduced directly onto the
column. Less volatile material can collect at the head of the column resulting in loss of
separation efficiency, and can introduce adsorptive sites in the column inlet. When dirty
samples are unavoidable, a retention gap can be helpful.
•
Real samples are often too concentrated for on-column injection and must be
diluted. As simple as this may seem, this often creates undesired peaks. Solvent impurities of milligrams per liter can disturb the sample profile. Subtraction of blank runs of
the solvent used for dilution may be helpful, as may the use of automatic samplers with
submicroliter capabilities.
•
Peak splitting or peak distortion can occur due to differing polarities of solvent,
stationary phase, and solutes. A retention gap can reduce these negative effects.
What is the Cool On-Column Inlet? 1-2
Features of the HP Cool On-Column Inlet
The HP cool on-column inlet gives you the ability to inject samples directly onto a cool capillary
column. Other features include:
• Temperature programming. Inlet temperature can be set to follow the oven program
or a separate program with rates up to 100°C/min. A fan shortens the cool-down time
between runs.
•
Pressure programming. The electronic pressure programming option provides very
accurate and precise control of column head pressure, resulting in retention time reproducibility of better than 0.02% RSD when there are no column effects. The inlet
pressure can be constant, programmed, or set to maintain a desired column flow rate.
Mass flow control can be maintained even at vacuum column outlet pressures. A safety
shutdown feature stops the run if the column breaks or pressure otherwise falls.
•
Liquid CO2 and N2 cooling. While an inlet cooling fan is standard, optional cryogenic
cooling of the inlet and oven can shorten the cycle time between runs.
•
Flexibility. Accommodates manual and automated injections with a conventional septa
or septumless device onto 530 \i, 320 fx, and 250 \i columns or precolumns, and manual
injections onto 200 \i columns.
What is the Cool On-Column Inlet? 1-3
Cool On-Column System
Block Diagram
External
plumbing
Carrier gas
Trap(s)
On-Column Gauge
inlet
(manual only)
Restrictor
Internal
plumbing
I
I
Pressure
regulator
Heater
block _
To
detector
\
Septum purge
regulator
Column
Cooling fan
Cool On-Column Inlet
Cross Section
Needle guide (different guides are
used for automatic or manual injection)
Septum
Spring
Carrier gas line in
Insert
Septum purge line out
Optional cryogenic
cooling
Heater block
Ferrule purge line
i
Ferrule
Inlet Septum Nut
Column
For a complete list of the consumables needed to operate the cool on-column inlet, see the
HP Analytical Supplies Catalog.
What is the Cool On-Column Inlet? 1-4
2
Using the Correct Insert,
Needle Guide, and Septum
The consumables used with the cool on-colunin inlet are different for manual and automatic
injection. For both injection techniques, the on-column inlet uses a small metal insert and a
spring inside the inlet body to ensure that the syringe needle is guided smoothly into the
column. The insert must be selected and installed before you install the column.
The correct insert and needle guide need to be installed before the column is installed. This
chapter lists the procedures for selecting the correct insert
Chapter 3 of this manual describes procedures for installing the column.
Insert, Needle Guide, and Septum 2-1
Selecting the Correct Insert
The small metal insert is installed in the inlet of the HP 5890 Series II GC to guide the syringe
needle smoothly into the column. The insert must correspond to the size of the column and syringe
needle you will use. Inserts are identified by the numbers of rings on them as shown in the
table below. All the inserts can be used with automatic and manual injection.
Column Size and Type
Insert
Number of Identification Rings
250 n
Silica
320 ^
Silica
530 urn
Al coated
530 ^m
Polyimide coated
After you select the correct insert, use the instructions in chapter 3 to check the
needle-to—column size before installing the column.
Insert, Needle Guide, and Septum 2-2
Changing the Needle Guide and Septum
Two needle guides are available for the on-column inlet, depending on whether you are using
fused silica or stainless steel syringe needles. The former guide requires a duckbill-type septum,
while the latter uses a small, disk-type septum.
To automatically inject into 250 \im and 320 \xm columns, use a 5 mm through-hole septum.
Stainless steel needle guide
and finned septa retainer
Fused silica needle guide
Duckbill septum
6 Disk septum
8 5-mm through -hole
septum
Note: The stainless steel top needle guide is only used for manual injection or automatic
injection with the HP 7673A automatic sampler. It can not be used with the HP 7673B
automatic sampler.
How to change the needle guide and septum:
1. Turn the oven OFF and set inlet pressure to 0.
2. Unscrew and remove the septa retainer.
3. Find the old septum. It is either inside the needle guide, or at the top of the inlet base. If
the septum is a disk septum, discard it. If it is a duckbill septum, you can reuse it if it has
not been leaking.
4. Find the small coil spring either in the top of the inlet base, or on the "bill" of a duckbill
septum. Place the spring at the top of the inlet base, if not already there. Do not lose or
damage the spring because it is required to keep the insert in position.
5. Replace the old septum with a new one appropriate for the needle guide you are using.
Place the septum on top of the coil spring in the top of the inlet base. For a duckbill
septum, make sure the "bill" points DOWN, into the inlet base, and is inside the coil
spring.
6. Install the new needle guide, tightening it finger-tight.
Insert, Needle Guide, and Septum 2-3
Selecting the Correct Needle Support Assembly
The following needle support assemblies are used for automatic injection into the on-column
inlet.
Needle support assembly
for 320 iim and 250 pun needles
.,
250 iim needle guide
Insert, Needle Guide, and Septum 2-4
Needle support assembly
for large needles
.,.
Using Retention Gaps and Other Precolumns
Precolumns are columns connected to the front of the analytical column. They
are commonly used to protect the analytical column from contamination.
A retention gap is a deactivated, uncoated (or thinly coated) precolumn. It is
used to increase sample resolution and decrease peak splitting. Retention gaps
have the effect of re-forming broad injection bands at the head of the column.
Retention gaps work well because when you first inject a sample, it exists as
both gas vapor and microdroplets. Without a retention gap, the gas vapor
begins partitioning immediately at the stationary phase. The microdroplets,
however, are carried further into the column by carrier gas and cause loss of
resolution and peak splitting. The addition of a retention gap in front of the
column prevents this premature partitioning until all of the microdroplets are
vaporized.
In general, the length of the retention gap required and type of deactivation
depend on injected volume and solvent polarity. A working rule of thumb is to
use between 0.3 and 1 m of retention gap per \i\ injected. For a 3 |xl sample,
use a retention gap that is between 1 and 3 m. The retention gap should be
wetted by the solvent, which means it should be deactivated with material of
similar polarity. Fused silica tubing is commercially available in a range of
diameters and deactivations for this purpose.
Press-fit connectors
Press-fit connectors are easy-to-use, general-purpose connectors for coupling
capillary columns of the same or different diameters.
Advantages: Press-fit connectors are inexpensive, have low dead volume,
fit most fused silica columns, have low mass (no thermal lag), and are
transparent. In most cases, simply pressing the column ends into the connector
is the only installation task; heat from the oven completes the seal.
Insert, Needle Guide, and Septum 2-5
Disadvantages: Because press-fit connectors are made of glass, these
connectors may be too reactive for some compounds. In addition, they may
need to be heated separately from the sample for a reliable seal, and they
expose a small amount of polyimide to the sample. If simply pressing the
column ends into the connector does not give a good seal, try the following
procedure:
1. Cut clean, square ends on the columns and wipe them with methanol to
remove fingerprints and dust.
2. Grasp one end of the connector with a folded tissue to avoid burned
fingers. Heat the other end with a hot-air gun (clamped in a ring stand so
hands are free) for about 30 seconds. Remove the connector from the heat
and immediately insert the column. Hold for about one minute while the
fitting cools and shrinks around the column. Repeat with the other
connection.
3. To finish forming the seal, place the press-fit connector in the gas
chromatograph oven, set the temperature above 200 °C, and run a low
carrier gas pressure. You should now be able to see the polyimide seal.
Butt Connectors
Butt connectors are popular for connecting precolumns to columns for
high-temperature use. Different size ferrules are used, depending on the size
of the columns. Because column ends are in contact with each other inside the
ferrule during tightening, exposure to ferrule material is minimized.
Purged Connectors
Purged connectors are commercially available for column connection. The
most complex of connector types, they purge the connection area and thus
minimize contamination.
Insert, Needle Guide, and Septum 2-6
3
Installing Columns
The correct insert and needle guide need to be installed before the column is installed. This
chapter lists the procedures for selecting the correct insert, checking the column size, installing
and aligning the inlet septum nut, installing the needle into the syringe barrel, and checking the
column for installation problems.
The table below shows your choices of needles and the ability to automate depending on the
column size.
Column id
Can 1 do automatic
injection?
Can 1 do manual
injection with a
fused silica needle?
Can 1 do manual
injection with a stainless
steel 26-gauge needle?
0.53 mm1
Yes
Yes
Yes
0.32 mm
Yes
Yes
0.25 mm
Yes
Yes
0.2 mm
Yes2
Yes
Yes, you use 2 6 - 3 2 gauge
(HP 5181-1266).
Yes, you use 2 6 - 3 2 gauge
(HP 5181-7442).
Yes2
1. This includes aluminum-coated columns.
2. If you use a 0.25 or 0.32 mm precolumn.
Installing Columns 3-1
Preparing a Fused Silica Capillary Column
This method gives a square cut for the column. If you are using precolumns or retention gaps,
see chapter 2 to select the right one, and connect it to the analytical column before you
continue.
1. Cut off the column end with a square cut according to the illustration below.
1. Score the column with a carbide knife.
3. Press to break.
2. Support opposite score mark on knife edge.
2. Wipe the column end with methanol to remove fingerprints and dust.
WARNING
Flying glass particles can cause eye injuries. Always wear safety glasses when
cutting fused silica columns.
Installing Columns 3-2
Checking the Needle-to-Column Size
After selecting an insert and before installing the column, you need to check the needle-tocolumn size because some manufacturers provide columns with ids that are too small. You may
bend your needle if you try to inject it into a smaller column. Use the insert that is the same
size as your syringe needle to verify that the column you plan to use is the correct size.
1. Identify the correct insert by the number of rings on it.
2. Insert the column into one end of the insert as shown below.
3. Insert the syringe needle through the other end of the insert and into the column. If the
needle cannot pass easily into the column, reverse the insert to try the needle and
column in the other end.
4. Notice into which end of the insert the column fits because that will be the end that goes
into the inlet first when you install the insert.
If the needle still cannot pass into the column, you may have a column with an incorrect id.
Check the column to make sure it is labeled correctly, and try a new column.
Installing Columns 3-3
Installing the Insert
1. Turn off the GC oven and set the inlet pressure to 0.
2. Remove the column, column nut, and ferrule.
3. On top of the oven, unscrew and remove the inlet septum retainer.
4. Replace the existing septum with a new one, and set the inlet septum retainer aside.
If the septum remains in the needle guide, do not remove it unless you want to change it.
Cool On-Column Inlet
Needle guide for
manual injection
Septum nut
Septum
Needle guide for fused
silica needles
Spring
Duckbill
Insert
Ferrule
Column nut
Column
5. Remove the spring from the inlet, and set it aside. Be careful not to lose or damage it
because you will use the spring to keep the new insert in position.
Installing Columns 3-4
6. Remove the existing insert from the inlet by pushing it out from below with a piece of
column. Store the insert for possible later use.
7. Drop the new insert straight into the inlet from the top. The end of the insert in which
you inserted the needle should be facing up; the end of the insert in which you inserted
the column should be facing down (see the previous section on checking the column
size). Use the identification rings to help you remember which way to install the insert.
8. Replace the spring on top of the insert
9. Follow the instruction in the next section to install the inlet septum nut and reassemble
the inlet.
Installing Columns 3-5
Aligning the Inlet Septum Nut
The inlet septum nut needs to be properly aligned to avoid bending the syringe needles during
injection.
1. To ensure proper alignment of the through-hole septa, thread the septum and the
septum nut onto a 26-gauge or larger needle or a piece of column or wire. The septum
should rest in the cavity in the nut as shown below. For 250 \im and 320 \im on-column
injections, the septum nut requires one of the 5 mm through-hole septa included in the
accessory kit.
2. Turn the needle over, and insert the wire, inlet septum nut, and septa into the inlet.
This end is inserted
into the inlet.
Inlet septum
Inlet septum nut
Needle
3. Tighten the septum nut fairly tightly so that you get a good seal.
4. Remove the needle from the inlet.
Installing Columns 3-6
Installing the Needle into the Syringe Barrel for
Automatic Injection
The stainless steel needles used for 250 |im and 320 (xm injections must be inserted into a glass
syringe barrel before they can be used in the HP 7673 automatic sampler.
1. Unscrew the syringe barrel cap, and remove the spring.
2. Select the correct size needle for the column you plan to use, and make sure the needle
has Teflon disk. If the syringe barrel does not have the Teflon disk, use the
instructions in the syringe box to wrap the needle yourself.
Syringe barrel
00
ff
Teflon disk
n.,..i,,.UH..l,,Hi,HU...I....TmW»
Needle
Spring Cap
il
3. Slide the spring and the cap down over the needle.
4. Insert the needle into the syringe barrel.
5. Screw the cap back on the syringe barrel.
Do not operate the injector without a syringe in place because the syringe latch
may interfere with the motor if it is allowed to swing freely.
Installing Columns 3-7
Installing a Fused Silica Capillary Column for
Automatic Injection
Column connections will be more successful if you prepare the columns properly. If you have
not prepared your column, use the instructions below to do so now.
1. Install a column nut and ferrule on the end of the column.
2. Cut off the column end with a square cut according to the illustration below.
1. Score the column with a carbide knife.
3. Press to break.
2. Support opposite score mark on knife edge.
3. Wipe the column end with methanol to remove fingerprints and dust.
4. Insert the column into the inlet base until it cannot go further.
WARNING
Flying glass particles can cause eye injuries. Always wear safety glasses when
cutting fused silica columns.
5. Finger tighten the column nut, making sure the column remains against the insert.
6. Use a wrench to tighten the column nut an additional 1/4-turn.
Installing Columns 3-8
7. Verify the column installation by manually pushing your syringe into the inlet. There
should be a gap of 3 mm or less between the septum nut and the syringe barrel.
If there is more than 3 mm between the syringe barrel and septum nut, your needle is not
reaching the column, and you will not be able to automate injection onto 250 ^im and 320 |xm
columns.
Syringe
3 mm or less
Septum nut
Installing Columns 3-9
Checking for Column Installation Problems
Using the Right Ferrules
Ferrules that are the wrong size or are improperly prepared cause leaks and contamination.
Here are some hints to avoid problems:
•
Graphite-containing ferrules should be baked at 250-300 °C for 30 minutes before
use because graphite is a good absorbent for organic compounds present in the atmosphere. Leave a petri dish of assorted ferrules in the GC oven to ensure a clean supply.
The ferrule should slide easily on the column, but not fall off under its own weight.
In this case, no more than 1/4-turn from finger tight is required to make a good seal.
If the column od is significantly smaller than the ferrule inside diameter, the column nut
will have to be tightened enough to compress the ferrule around the
column. This is usually not a problem with easily deformed graphite ferrules. Harder
ferrules may require so much torque that the inlet fitting may be bent, or the nut may be
broken. In addition, the ferrule may split and yield a leak. With hard ferrules, it is better
to start with an undersize hole and drill it to fit the column.
• Vespel ferrules can be more leaktight than graphite, but have a lower temperature
limit. They should be retightened after a few temperature cycles to ensure a good seal.
Be sure to use the correct ferrule for the size column you are using.
Installing Columns 3-10
4
Setting Inlet Pressure
Your cool on-column inlet is equipped with either manual pressure control or electronic
pressure control. Read "Selecting the Best Inlet Pressure" in this chapter, and then go to the
instructions for either manual or electronic pressure control, depending on your unit.
Setting Inlet Pressure 4-1
Selecting the Best Inlet Pressure
This table is a starting point for selecting pressure, based on column length and bore.
Pressure at Optimal Linear Velocity in kPa (psi) Based on Column id and Length
Length (m)
25
12
0.20
id
0.32
(mm)
0.53
50
135 (19.6)
223 (32.4)
347 (50.3)
45 (6.5)
82(11.9)
137(19.9)
11(1.7)
23 (3.3)
42(6.1)
Assumptions:
Carrier gas: He
Temperature: 100°C
Optimal linear velocity: 30-60 cm/sec.
When using the 5 m x 0.53 mm id checkout column, suggested pressure is 15 kPa (2.2 psi) with
helium gas flow of 20 ml/min.
Choosing Pressure for a Desired Linear Velocity
Linear velocity through the column is measured by injecting a sample containing an unretained
component (typically CH4).
The observed retention time for the unretained component is compared to an expected
retention time (t r ) calculated from the desired linear flow velocity (u) and the length of the
column:
expected (lnmln) = 1.67 X
Column length (m)
Linear flow velocity (cm/sec)
With repeated injection of the unretained component, adjust the pressure as necessary to
obtain the expected retention time for the desired linear velocity.
To verify flow rate through the column:
1. Turn off detector gases.
2. Measure flow using a bubble flow meter connected at the detector exhaust vent.
Setting Inlet Pressure 4-2
Checking Vent Flow Rate
The septum purge vent is not adjustable, but you should check the flow. Do not cap off the flow
from the purge vent.
Carrier Gas Type
Approximate Flow
H2
He
N2
Ar - Me
12 ±3
12 ± 3
12 ±.3
12 ± 3
ml/min
ml/min
ml/min
ml/min
WARNING
Hydrogen gas is flammable. If you use hydrogen carrier gas, either vent the
purge flow appropriately or add a needle valve restrictor at the vent fitting and
adjust the flow down.
Safety Shutdown
Programmable cool on-column inlets that are equipped with electronic pressure control have a
safety shutdown feature to prevent gas leaks from creating a safety hazard. If the system
cannot reach a pressure setpoint, the system beeps. After about two minutes, the beeping stops
and the following message appears on the display:
ACTUAL
SETPOINT
EPPB: SAFETY SHUTDOWN
The system will shut down by turning off all electronic pressure and heated zones and locking
the keyboard.
See chapter 7, Maintanence and Troubleshooting, for more information about safety shutdown.
Note: These safety shutdown procedures apply to EPC boards with a mainboard ROM part
number HP 05890-80310 or higher.
Setting Inlet Pressure 4-3
Setting Inlet Pressure Using Electronic Pressure Control
If your GC is equipped with electronic pressure control, you can set constant pressure
or create a pressure program with multiple ramps.
Before You Start
1. Be sure carrier source pressure is at least 138 kPa (20 psi) greater than the maximum
desired inlet pressure.
2. Select the pressure units you would like to use.
To change the units, press EIPI&I) I 1 1 1 ENTER 1, and then select
1 2 I = bar, or
C O =kPa.
3. From the keyboard, set the pressure.
Set the oven and heated zone temperatures. Be sure the detector is turned on, and its output
signal is assigned to the correct channel.
Setting Inlet Pressure 4-4
Zeroing Pressure
An inlet with electronic pressure control is zeroed when it is shipped. However, you should
check this periodically. To zero the pressure, press:
1.
:il i
INJBPRES
o \ [ • \
ENTER 1 Set inlet B pressure to 0.0.
Allow enough time for the column to completely depressurize. Remove the septa
retainer or disconnect the source pressure to depressurze the column more quickly.
2. To zero channel B, press
where value is the zero offset value shown on the GC display labelled "actual".
4.
M
[
INJ B PRES 1 | o I [ • I
ENTER
1 Set inlet B pressure to 0.0.
Allow enough time for the column to completely depressurize. Remove the septa
retainer or disconnect the source pressure to depressurze the column more quickly.
5. To zero channel A, set inlet A pressure to 0.0, then press
where value is the zero offset value shown on the GC display labelled "actual".
Setting Inlet Pressure 4-5
Setting Constant Pressure
Follow the example below to set Injector B pressure to 10 psi.
il
L
INJBPRESJ [ 1
ENTER I
ACTUAL
10.0
&
C
INIT TIME
set inlet B pressure to 10 psi.
SETPOINT
10.0
The GC display looks like this.
Set initial time to 650 (max).
1
Note: If the initial time is less than the total run time, the inlet B pressure will because it is
being controled by the constant flow mode. Turn off the flow control option to avoid having
the pressure change during the run. To do this, press the following keys until the display looks
like the one below:
ACTUAL
B CONST FLOW
OFF
The GC display looks like this.
Setting Pressure Programs (1 Ramp)
This example shows how to start with Injector B pressure at 10 psi for 1 minute, then ramp at
5 psi/min to 20 psi, and remain there for 2 minutes.
INJBPRES
1
[
INIT VALUE
^ } [ o 1 [ ENTER 1
Set Injector B initial pressure at 10 psi.
Set initial time at 1 minute.
Set ramp at 5 psi/min.
Set final pressure at 20 psi.
Set final time at 2 minutes.
Note: The oven program determines the run time of the analysis. If the inlet pressure program
is shorter than the oven temperature program, the inlet pressure will go into the constant flow
mode for the remainder of the run. To prevent this, set the pressure program longer than the
oven temperature program.
Setting Inlet Pressure 4-6
Setting Pressure Programs (2 and 3 Ramps)
To add a second and third ramp to the above pressure program, press the following keys after
you enter the previous example:
Set the second ramp at 2 psi/min.
ENTER
1 Set the second final pressure at 26 psi.
ENTER |
Set the second final time at 2 minutes.
Set the third ramp at 4 psi/min.
ENTER I
ENTER I
set the third final pressure at 30 psi.
Set the third final time at 5 minutes.
Checking the Pressure Program
Display the pressure program by pressing any pressure program key, followed by I ENTER 1.
Successively press [ ENTER ) to scroll through the program.
Note: The oven program determines the run time of the analysis. If the inlet pressure program
is shorter than the oven temperature program, the inlet pressure will go into the constant flow
mode for the remainder of the run. To prevent a pressure program from going into constant
flow mode, be sure to set the pressure program longer than the oven temperature program.
Setting Inlet Pressure 4-7
Using the Constant Mass Flow Modes
If your system is equipped with electronic pressure control, you can program the inlet to
maintain constant mass flow. To use the constant mass flow modes:
1. Select the gas type.
FLOW PARAM
FLOW PARAM
ACTUAL
1
Scroll to select gas type.
SETPOINT
The GC display now looks like this. Press
1= Helium, 2 = Nitrogen, 3 = Hydrogen,
4 = Argon/Methane.
m>P B
2. Press C FLOWPARAM J again until you see the constant flow display.
ACTUAL
SETPOINT
WPP & CONST FLOW OFF
3. Select the option you wish to use.
i 0FF H = constant flow mode off.
[ ON II = constant flow mode on. You set pressure at oven initial temperature after
turning on the constant flow feature.
Setting Inlet Pressure 4-8
Turning Off Constant Flow
When you select t 0FF Jl, you turn off the constant flow mode. You must seW.t [""OFF )| if you
wish to create independent pressure programs.
Turning On Constant FlowYou Set Initial Pressure, and the GC Maintains Initial Flow
When you select t ON D , you turn on the constant flow mode. You can set an initial pressure
at oven initial temperature as follows:
P&ag:i$ [
INJ B PRES
1 [ 1 I | o I [ENTER \
Set starting pressure to give a constant flow.
The GC will then maintain the initial flow throughout the run by automatically adjusting
pressure.
Note: Make sure the oven is equilibrated to initial temperature when the initial pressure is set;
an incorrect flow will result if initial pressure is set before initial oven temperature is reached.
Constant Flow Hint
You can check the flow through the column by turning off the detector gases and measuring the
flow using a bubble flow meter and the GC stopwatch feature. Check the Operating Manual for
more details.
Setting Inlet Pressure 4-9
Setting Mass Flow Rate
If your system is equipped with electronic pressure control, you can set mass flow rate. This
flow control capability is accomplished through the electronic pressure control function.
For example, when a constant pressure is set, mass flow is displayed (monitoring mass flow).
Entering a new mass flow value will automatically set a new constant pressure to obtain the
flow value entered.
Note: Before setting mass flow, the correct column parameters (column length, column
diameter, and gas type) must be entered.
Follow the example below to set Injector B flow to 10 ml/min.
1. Select the gas type.
[
FLOWPARAM
1 [
FLOWPARAM
ACTUAL
&
"
L|~
1
Scroll to select gas type.
SETPOINT
Mf
•••••"
I
'
The GC display now looks like this. Press
1 = Helium, 2 = Nitrogen, 3 = Hydrogen,
4 = Argon/Methane.
2. Enter the column diameter.
Press C FLOW PARAM 1 again until you see the column diameter (id) display.
ACTUAL
B:
Column Ola
SETPOINT
.XXXmm
The GC display looks like this.
The column diameter must be entered in microns (i.e., 200 |im, 530
I 5 I
t 3 I
1 0 I
Setting Inlet Pressure 4-10
[ ENTER 1
Sets the column diameter to 0.530 mm.
3. Enter the column length.
Press (T
FLOWPARAM
8:
J again until you see the column length display.
ACTUAL
SETPOINT
Column Lart
XX.XXM
The GC display looks like this.
Column length must be entered in meters. If exact column length is unknown, refer
to "Determining Corrected Column Length".
[ 2 \
( 5 1
[ ENTER I
Sets the column length to 25 meters.
4. Set the column B desired flow rate.
Press I
COLUMN
J I FLOW J until you see the mass flow control display.
B
ACTUAL
SETPOINT
10*0
MI/MItt
The GC display looks like this.
Sets inlet B flow to 10 ml/min.
Note: Inlet B pressure will change to a value needed to produce 10 ml/min.
Setting Inlet Pressure 4-11
Determining the Corrected Column Length
When you want to set or display mass column flow, you must determine a corrected length and
diameter for an equivalent open tubular column.
(
1. Press
display.
FLOWPARAM
I
(
FLOWPARAM
|
untU
you see the column diameter
Set column diameter to its nominal inner diameter value (100 \xm, 200 \xm, 530
etc.). For a packed column, enter 530 \xm.
2. Press C
FLOWPARAM
1 until you see the column length display.
Set column length to its nominal length in meters.
3. Select the gas type.
Press 8188311$ I
FLOWPARAM
1 C FLOWPARAM
ACTUAL
jj£
1
Scroll to select gas type.
SETPOINT
figf
'"•*
I The GC display now looks like this. Press
I 1 = Helium, 2 = Nitrogen, 3 = Hydrogen,
4 = Argon/Methane.
4. Press I CLEAR ) ( FLOW 1 C ^ i until the display reads:
COLUMN
B
ACTUAL
SETPOINT
97.5
Cm/Sec
This is the computed average linear velocity ( u ) for the estimated length column (10 m)
at the given temperature.
Setting Inlet Pressure 4-12
5. Inject an unretained component and determine its retention time in minutes.
This is t o Actual.
6. Calculate corrected column length as:
-concerted^
/^Actual
I "
—
X u \
j
,
where:
•< corrected = corrected column length in meters
o Actual = retention time of unretained component in minutes
u = average linear velocity in cm/sec
Enter the value calculated from the above formula as the column length in step 3 of "Setting
Mass Flow".
Setting Inlet Pressure 4-13
Setting Flow Programs
Flow programs can be set indirectly through pressure programming once gas type, column
diameter, and column length have been entered.
Note: Column length must be entered in meters. If exact column length is unknown, or if a
packed column is in use, refer to "Determining Corrected Column Length". This example
shows how to obtain pressure values necessary to create a pressure program to set column B
flow at 4 ml/min, then end with 7 ml/min.
Setting Inlet Pressure 4-14
This example shows how to obtain pressure values necessary to create a pressure program to set
column B flow at 4 ml/min, then end with 7 ml/min.
1. Press
ICLEAR
_FLOWJ
COLUMN
2. Press I 4 I
(ENTER
[ FLOW I until the display reads:
B
ACTUAL
SETPOINT
XX.X
ml/mfci
) until the display reads:
ACTUAL
COLUMN
3. Press
C
The display looks like this.
B
SETPOINT
4*0
The display looks like this.
ii the display reads:
INJ B PRES
ACTUAL
SETPOINT
10.0
ZPP B
The GC display looks like this. This will
be injector B pressure initial value.
4. Press [ FLOW 1 [ FLOW 1 until the display reads:
ACTUAL
COLUMN
B
4.0
SETPOINT
ml/milt j
The display looks like this.
5. Press [ 7 1 [ ENTER 1 until the display reads:
ACTUAL
COLUMN B
6.
C
INJ B PRES
7,0
The display looks like this.
l e n t i l the display reads:
ACTUAL
EPP B
SETPOINT
SETPOINT
The GC display looks like this. This will
be injector B pressure final value.
Use the pressure values obtained from this procedure when you set a pressure program. Initial
time, ramp rate, and final time are entered as part of setting the pressure program (see
"Setting Pressure Programs").
Setting Inlet Pressure 4-15
Setting Average Linear Velocity
If your system is equipped with electronic pressure control, you can set average linear velocity.
Like mass flow control, the average linear velocity capability is accomplished through the
electronic pressure control function.
For example, when a constant pressure is set, average linear velocity is displayed (while you are
monitoring average linear velocity). Entering a new average linear velocity value will automatically set a new constant pressure (and flow rate) to obtain the velocity value entered.
Note: Before setting average linear velocity, the correct column parameters (column length,
column diameter, and gas type) must be entered.
To set average linear velocity, perform steps 1 through 3 of "Setting Mass Flow". Then follow
the example below to set the average linear velocity to 100 cm/sec.
1. Set the column B desired average linear velocity.
Press 1 CLEAR 11 FLOW ) I FLOW } until the display reads:
ACTUAL
COLUMN
B
97J
Press
Cm/S«c|
ENTER I
ACTUAL
COLUMN
SETPOINT
B
100*0
The GC display looks like this.
Set inlet B linear velocity to 100 cm/sec.
SETPOINT
The GC display looks like this.
Note: The pressure and flow for Inlet B will change to a value needed to produce 100 cm/sec.
Setting Inlet Pressure 4-16
Using Vacuum Compensation Mode
Vacuum compensation should be used anytime a mass spectrometer is used, to allow column
outlet pressure to be at vacuum conditions. With vacuum compensation and constant flow
on, a constant mass flow is delivered to the mass spectrometer throughout a temperature
programmed run. This results in a constant mass spectrometer ionization current level and
a 15 to 30% shorter run time.
1. Turn on vacuum compensation:
Press M M t FLOWPARAM I { FLOWPARAM |
display.
ACTUAL
0
VAC COMP
until y o u see t h e column
compensation
SETPOINT
OFF
The GC display looks like this.
To turn on column compensation, press l£HJ.
To turn off column compensation, press (0FFJ.
After you turn on the vacuum compensation feature, you enter the desired pressure setting.
Note: HP 5890 Series II GC instruments with electronic pressure control that were built before
July 1,1990 will display the message change EPC ROM. When this occurs, contact
Hewlett-Packard to get an updated ROM.
Setting Inlet Pressure 4-17
Setting Pressure Using Manual Control
If your GC is equipped with manual pressure control, follow these instructions to set pressure.
1. Set oven and heated zone temperatures. Be sure the detector is turned on, and the
output signal is assigned to the correct channel.
Flow Panel for Manual Pressure Control
INJECTION PORT A
Pressure
gauge
Pressure
regulator
Septum
purge vent
2. Be sure the carrier source pressure is at least 138 kPa (20 psi) greater than the selected
inlet pressure.
3. Select the inlet pressure using the pressure regulator.
Setting Inlet Pressure 4-18
5
Setting Inlet Temperature
Guidelines for Selecting Inlet Temperature
1. Determine the oven temperature program that gives you good component separation.
The starting inlet temperature is usually similar to the starting oven temperature, which
is at or below the boiling point of the solvent.
2. Determine the total time of the run.
3. To save time between runs, set the inlet temperature program time shorter than the total
time of the run. This way, the inlet will begin the cooling process earlier.
4. For best retention time reproducibility, use an oven equilibrium time of about 3 minutes
(1 minute if cryogenic cooling is used).
Setting Inlet Temperature 5-1
Setting the Inlet Temperature to Follow the Oven Temperature
(Oven Track)
The oven track feature sets the inlet temperature 3°C higher than the oven at all times to
optimize repeatability. Oven track is on when you receive your GC from the factory. To turn
on oven track:
J M ^ L O V i N TRACK 1
Turn on the oven track option.
ACTUAL
SETPOINT
The GC display looks like this.
)NU A
Creating an Independent Inlet Temperature Program
This example shows how to start with Injector B temperature at 60 °C for 1 minute, then ramp
at 20°C/min to 100°C, and remain there for 2.2 minutes.
C INJBTEMP
C
INHUME
1 L
INIT VALUE
1
ENTER 1 Set initial inlet temperature.
1
Set initial time.
Set initial rate.
Set final temperature.
I
FINAL TIME
t
INJBTEMP
Set final time.
1L
INIT VALUE
1
[ ENTER 1 [ ENTER
Scroll through inlet program.
To optimize repeatability when creating inlet temperature programs, be sure that the inlet
temperature is always at least 3° higher than the oven temperature. You do this by turning
on the oven track mode.
If the message IN J B Oven Track On appears on the display, press Q^D *° disable the
oven temperature tracking. You can now program the inlet temperature independently of the
oven temperature.
Setting Inlet Temperature 5-2
Using Cryogenic Oven Cooling
Oven temperature may be controlled below ambient when a cryogenic valve is present.
Cryogenic control setpoints are described in the following table:
Cryogenic Control Setpoint
Description
CRYO ON
Enables subambient control of the oven.
CRYO OFF
Disables subambient cooling of the oven; the
default state for the cryogenic valve is off.
CRYO BLAST ON
Enables very fast cooldown time after a run.
CRYO BLAST OFF
Disables very fast cooling of the oven.
AMBIENT
CRYO FAULT ON/OFF
CRYO TIMEOUT XXX MIN
Sets optimal temperature control for efficient use
of cryogenic fluid. The default temperature
setting is 25 °C.
A fault occurs when the oven does not reach set
temperature after 17 minutes of continuous cryo
operation. The oven turns off, and the message
WARN:OVEN SHUT OFF is displayed. Turning off
Cryo Fault will disable this feature.
A cryo timeout occurs when a run does not start within
a specified time (10 to 120 minutes) after the oven
equilibrates. Turning off Cryo Timeout will disable this
feature. The default is ON for 30 minutes.
When the cryogenic valve is turned on, it operates automatically to obtain an oven temperature
when there is demand for coolant to be supplied to the oven.
When cryogenic cooling is not needed, cryogenic valve operation must be turned off. If this is
not done, proper oven temperature control may not be possible, particularly at temperatures
near ambient.
Setting Inlet Temperature 5-3
The Cryo Blast feature can operate together with or independently of Cryo On/Off. Cryo Blast
cools the oven faster after a run than it would under normal cryogenic operation. This allows
the HP 5890 GC to be ready for the next run earlier than it would without Cryo Blast on. This
feature is useful when maximum sample throughput is necessary.
Successively pressing the [ CRYO PARAM 1 key scrolls through the cryogenic valve operation
functions. Use the following key sequence to turn cryogenic operation or blast on and off:
or
CRYOPARAM_J
[OFF
| ON
To turn Cryo Blast operation on or off, use the following key sequence:
ON
Press
t
I or
(OFF
1 Scroll to Cryo Blast and nressl ON
CRYO PARAM
An example key sequence to change the ambient temperature setting to 23°C is:
C
CRYO PARAM
1
SCROLL TO AMBIENT
You can set the ambient temperature to allow fine tuning of cryogenic operation. The default
setting is 25 °C. It does not need to be changed for most applications. For more information
about adjusting the ambient cryogenic setting, see the HP 5890 Series II Reference Manual.
The following figure shows the displays associated with disabling and enabling automatic
cryogenic valve operation.
Automatic Cryogenic Valve Displays
CBYO
CRYO
ACTUAL
SETPOINT
ACTUAL
SETPOINT
ACTUAL
SETPOINT
ON
OFF
1
CRYO FAULT O N
ACTUAL
CRYO TIMEOUT 20 Min
Setting Inlet Temperature 5-4
SETPOINT
6
Making Injections
The HP 5890 Series II cool on-column inlet allows you to inject sample volumes onto columns
that are 250 \im or larger using automatic and manual injection techniques.
Before the Injection
Here is a checklist for injecting into a cool on-column inlet:
• The initial oven temperature should be 25 °C below the boiling point of the solvent.
• The sample injection must be done quickly and smoothly to ensure that the sample is
introduced in liquid form.
• The syringe needle must be withdrawn immediately after injection.
• The sample amount injected, both total volume and component concentration, is
important; large volumes may cause band broadening, particularly for components with
boiling points approximately 150°C greater than that of the solvent.
• The recommended sample injection volume is 0.5 |xl or less for 0.20 mm columns.
For injections with the HP 7673A automatic sampler that are less than 1 jxl, use the
nanoliter adapter kit.
• With automatic injection, make sure your syringe and inlet assembly are aligned
correctly, or you may bend your needle.
Making Injections 6-1
Can I Automate?
Yes, the special considerations for automatic injection are listed starting on page 6-8. The
following table shows your choices of needles and automating ability based on the column used.
Column id
Can 1 do automatic
injection?
Can 1 do manual
injection with a
fused silica needle?
Can 1 do manual
injection with a stainless
steel 26-gauge needle?
0.53 mm1
Yes
Yes
Yes
0.32 mm
Yes
Yes
0.25 mm
Yes
Yes
0.2 mm
Yes2
Yes
Yes, you use 26-32 gauge
(HP 5181-1266).
Yes, you use 2 6 - 3 2 gauge
(HP 5181-7442).
Yes2
1. This includes aluminum-coated columns.
2. If you use a 0.25 or 0.32 mm precolumn.
Making Injections 6-2
Manual Injection Technique with Stainless Steel Needles
When you are injecting by hand using stainless steel needles, make sure the stainless steel
needle guide and disk-type septum are installed. To perform the injection:
1. Immerse the syringe needle in sample; pump the syringe plunger to expel air from the
barrel and needle.
2. Draw the sample into the syringe.
3. Remove the needle from the sample and draw about 1 (xl of air into the syringe.
4. Wipe the needle dry it if it is wet.
5. Guide the needle straight into the needle guide, pierce the septum, and insert the needle
fully into the inlet.
6. Start the run, depress the syringe plunger as quickly as possible, and withdraw the needle
from the inlet.
Note: These steps should be done smoothly, with minimal delay.
Making Injections 6-3
Manual Injection Technique with Fused Silica Needles
Note: When injecting with fused silica needles, be sure the initial pressure is less than 30 psi.
Higher pressures will make needle insertion difficult.
When fused silica needles are required for injection onto 320 \i and smaller diameter columns,
follow these steps for injection:
1. Immerse the syringe needle in sample and pump the syringe plunger to expel air from the
barrel and needle.
2. Draw the sample into the syringe. Allow enough time for fluids to pass through the small
bore of the needle.
3. Remove the needle from the sample and draw about 1 |xl of air into the syringe. Wipe the
needle with a tissue wetted with solvent.
4. Press the needle guide fully down to open the duckbill.
WARNING
The inlet needle guide may be hot! Use a pencil to depress
the needle guide.
5. Hold the needle guide down for about 3 seconds to depressurize the column. This
prevents loss of sample due to backflow of carrier gas. When you do this with an
electronic pressure controlled system, it will start to beep while the column is depressurised. The beeps will stop after the system repressurises.
6. While holding the needle guide down, guide the needle straight into the needle guide
and fully insert it into the inlet.
Hint: If the needle does not go in all the way, try rotating the syringe and slightly releasing pressure on the needle guide.
7. Once the needle is fully inserted, release the needle guide. Allow 1 to 2 seconds for
backpressure on the duckbill to seal it around the inserted needle.
8. Start the run, depress the syringe plunger as quickly as possible, and withdraw the needle
from the inlet.
Making Injections 6-4
Replacing the Fused Silica Syringe Needle
Needle
Ferrule sleeve
Teflon ferrule
1. If you are cutting replacement needles directly from fused silica column material:
a. Column material for making needles must have an od smaller than both the id of the
on-column inlet (0.23 mm) and the id of the installed column.
b. Column material must be washed free of active stationary phase.
c. Score the column material about 1/4-inch from its end. Break off the end and discard.
Then measure, score, and break off a 115 +. 5 mm length to use as the syringe needle.
2. Hold the syringe vertically, and insert the fused silica needle so it is visible inside the
syringe barrel. If the fused silica needle cannot be inserted into the syringe barrel, the
Teflon ferrule may be blocked. You may need to replace the ferrule.
3. When the needle is inserted, tighten the retaining nut to firm finger tightness. Pull the
needle gently to be sure the Teflon ferrule has formed a tight seal with the needle.
Tighten the retaining nut further, if necessary.
Making Injections 6-5
4. Loosen the retaining nut just enough so the needle is again free. Depress the syringe
plunger slowly until it pushes the needle to the end of the barrel, then tighten the
retaining nut to firm finger tightness.
5. Use a suitable solvent to rinse the syringe and check for leaks or blocks.
Leaks (inability to eliminate air bubbles) may be fixed by further tightening the retaining
nut. Blocks (or serious leaks) require repeating this procedure.
Note: The Teflon ferrule may lose its seal in time. If so, first retighten the retaining nut, and if
the seal still leaks, install a new Teflon ferrule and needle.
Replacing the Universal Syringe Needle
The stainless steel needles used for 250 \im and 320 \xm injections must be inserted into a glass
syringe barrel before they can be used in the HP 7673 Automatic Sampler.
To insert a needle into a syringe barrel, follow the procedure below:
1. Unscrew the syringe barrel cap and remove the spring.
2. Select the correct size needle for the column you plan to use, and make sure the needle
has Teflon disk, as shown in the picture below. If the syringe barrel does not have the
Teflon disk, use the instructions in the syringe box to wrap the needle yourself.
3. Slide the spring and the cap down over the needle.
4. Insert the needle into the syringe barrel.
5. Screw the cap back on the syringe barrel.
Syringe barrel
oo
[|
Making Injections 6-6
Teflon disk
\
Hl,4,4,4,44,4,4l4iiP
Needle
Spring Cap
I
I
Automatic Injection Considerations
Syringe needles can be made of stainless steel (size 26 gauge or tapered 26—23 gauge) and
made from fused silica (size 530 \im, 320 \xm, or 250 [xm). To operate using 250 ^m and 320 f
needles, proceed to the next page.
When you are performing analyses using an automatic sampler, you must use the disk type
septum for 530 urn and larger needles and the through-hole septa for smaller needles. In
addition, consider the following:
• For HP 18593B injector modules, remove the needle guide top from the septum nut
base assembly. Save the needle guide top to realign the bracket.
• For HP 18593A injector modules, leave the needle guide top on the septum nut base
assembly. The cup-shaped top is part of the injector mounting scheme.
Septum nut
(T^r^J
base assembly ^ ^ ^ ^ ?
Needle
guide top
Making Injections 6-7
Automated Injection Technique
You can automatically inject into 250 |xm, 320 |xm, 530 urn columns using the on-column inlet
However, be sure to align the needle, inlet, and column to ensure the best performance.
Use this checklist to make sure you are ready to inject using the HP 7673 Automatic Sampler.
For complete instructions on how to operate and trouble the automatic sampler, see the
HP 7376 Automatic Sampler Operating and Installation Manual.
D The sample vials are half full.
• The vial cap is centered, is not wrinkled, and the septum is flat
• You are using the correct vial cap for the application. If you are injecting
into 250 nm or 320 nm columns, use the thin-membraned caps
• The sample inserts and vials match the run parameters
HP 3396
•
•
•
•
Each solvent bottle contains 4.5 ml of fresh solvent.
Waste bottle is clean and empty.
You are using 2 waste bottles with the tray.
The number of solvent bottles is limited to number of sample vials.
n
•
•
The syringe is the correct design and size for your application.
The plunger carrier screw is tight.
The needle is aligned with the septum retainer nut.
D
You have installed the correct septum type.
•
The septum has been used for fewer than 200 injections.
•
The injector run parameters are set correctly
• Injection mode matches type of inlet.
• Number of injections per vial is less than 5.
Making Injections 6-8
Performing Automated Injection onto 250 urn and
320 |nm Columns
This section lists the proper procedures for changing, aligning, and installing the needle support
assembly to adapt from 530 \im injection to 250 \im or 320 |xm injections. To inject onto
250 jim or 320 fxm columns, you first change the needle support assembly.
Removing the 530 |xm Needle Support Assembly
Plunger carrier
Plunger screw
Flange guide
Syringe latch
Syringe clip
Hold here
to remove
« * - Syringe
Large needle
support assembly
1. Lay the injector module on its back on a flat surface, and open the injector door.
2. Loosen the plunger screw and slide the loop of the plunger carrier up as far as it will go.
3. Swing the syringe latch counterclockwise to unlock the syringe.
4. With your finger under the upper portion of the syringe barrel (just above the syringe
latch), pull the syringe up and gently remove it.
5. With your finger under the brass fitting of the 530 \im needle support assembly, pull up
gently to release and remove the assembly.
Making Injections 6-9
Installing the 250 \im and 320 |xm Needle Support Assembly
1. Holding the new needle support assembly in your right hand, push the bearing down
the shaft of the assembly about 3 inches.
2. Insert the upper end of the rod into the black plastic guide to the right of the plunger
carrier loop.
3. Align the bearing on the needle support assembly with the plastic bearing clip to the right
of the syringe latch.
Making Injections 6-10
4. Push the assembly down into place. Make sure the slide lies flat on the tracks of the syringe carriage and above the so that it glides up and down as shown in the illustration
below.
Making Injections 6-11
Installing the Syringe into the Needle Support Assembly
When a syringe is worn, replace it with a new one using the following steps:
1. If you have removed the injector module to replace the needle support assembly, place
the module back on the HP 5890 Series II GC oven or on a parking post if you have one.
2. Open the injector door.
3. Pass the syringe needle through the hole of the small, needle guide in the needle support
foot.
4. Align the flange with the flange guide and syringe clip, and gently press the syringe into
place, keeping the needle in the hole of the needle guide. Be careful not to bend the
needle during this step.
Making Injections 6-12
5. Close the syringe latch by swinging it clockwise.
Plunger carrier
Flange guide
Flange
Syringe latch
Syringe clip
Needle
support foot
Do not operate the injector without a syringe in place because the syringe latch may interfere
with the motor if it is allowed to swing freely.
6. Move the plunger loop down, and tighten the plunger screw.
7. Move the plunger loop up and down to make sure the plunger is moving with the carrier.
8. Make sure the needle is aligned with the needle guide in the foot by moving the slide up
and down. The needle should slide smoothly in the needle guide.
Failure to use the correct size on-column syringe when injecting into an on-column inlet could
damage the injector, syringe, and column.
Making Injections 6-13
7
Maintenance and Troubleshooting
This section lists procedures to keep your inlet functioning properly, including:
• Cleaning and care.
• Pressure and temperature control problems.
• Safety shutdown and alarm relay
• Septum problems.
• Syringe problems.
• Sampler vial cap septum problems.
• FID flameout problems.
• Proper configuration.
• Peak broadening and split peaks.
• Useful tools.
Maintenance and Troubleshooting 7-1
Cleaning and Care
Most laboratories have airborne lint and dust that accumulates on the needle guide and can
be carried into the inlet or column on the syringe needle. Particulate matter in the inlet
interferes with easy passage of the syringe needle. If dirt enters the column, it can alter the
chromatography.
Clean the stainless steel needle guide, spring, and insert by sonication for 1 minute in aqueous
detergent, then in distilled water. Rinse with methanol, and air dry. Check the insert for
cleanliness with a magnifier.
Clean the fused silica needle guide by forcing methanol through the needle with a squeeze
bottle.
Maintenance and Troubleshooting 7-2
Troubleshooting Automatic and Manual Injections
If you have checked these possible causes and still have a problem, call your nearest HewlettPackard Service office.
Symptom
Possible Cause
Corrective or Preventive Action
Not enough
Septum leaks or is missing.
Check system for leaks.
pressure (safety
shutdown activated). Column is broken.
Column ferrule seal leaks.
Gas supply is off.
Supply pressure is inadequate.
Desired pressure may not be
achievable with the column in use.
Check your configuration in
"Proper Configuration".
Pressure goes
to 0 or maximum.
Configuration is wrong.
Not Ready light
flickers (oscillating
pressure).
Septum or column connection
leaks.
Pressure set higher than the
operating limit.
Not Ready light
flickers (oscillating
temperature).
Configuration is wrong.
See "Proper Configuration".
Inlet temperature equilibration
time is too short.
Increase equilibration time,
Pressure and
temperature
are not controllable.
Configuration is wrong.
See "Proper Configuration".
Inlet cools down
very slowly.
Fan is either not running or
blowing away from inlet.
Check that the fan is running.
Maintenance and Troubleshooting 7-3
Symptom
Possible Cause
Bent needle
Incorrectly installed needle Check needle support assembly
support assembly
installation.
Corrective or Preventive Action
Defective needle
Check each syringe before installation
to make sure needle is straight.
Wrong vial caps
Use only thin-membrane vial caps
(HP p/n 5062-3582).
Incorrect insert
Make sure the insert is the correct size
for the column and needle you use.
Also check that the insert is installed
correctly.
Overcrimped vial caps
See pages 3-4 and 3-5 in the HP 7673
Automatic Sampler Operating Manual
for instructions on crimping vial caps.
Worn or damaged rubber
needle guide
Check the needle guide on the needle
support foot every time you change the
inlet septum, and replace if necessary.
Incorrect inlet septum
Use only a 5-mm septum with a
through-hole.
Poor alignment of inlet
septum and septum nut
Align the inlet septum and septum nut
according to the instructions provided
in this manual.
Incorrect column
internal diameter
Check the internal diameter of the
column by using the appropriate
insert.
Closed inlet septum hole
Replace the septum.
Poor alignment of the inlet See the HP 5890 Series II Operating
and the automatic injector Manual for alignment instructions.
Maintenance and Troubleshooting 7-4
Symptom
Possible Cause
Corrective and Preventive Action
No peaks or
unexpectedly
small peaks
Plugged syringe needle
Replace the needle, or clean it with wire.
Worn syringe barrel
Replace the syringe often, or use a gastight syringe. (Under high pressure, the
sample is pushed upward through the
gap between the plunger and the glass
barrel, and a worn plunger can lead to
sample loss.)
Loose removable needle
Make sure syringe barrel caps are
screwed on tightly and that the Teflon
disk is wrapped tightly.
Incorrectly placed or
missing Teflon disk on
the syringe needle
Check every syringe needle to make
sure the Teflon disk is present and
correctly placed.
Poor precision;
Worn syringe barrel
poor repeatability;
large standard
deviation
Replace the syringe often. (Under high
pressure, the sample is pushed upward
through the gap between the plunger and
the glass barrel, and a worn plunger can
lead to sample loss.)
Loose removable needle
Make sure syringe barrel caps are
screwed on tightly and that the Teflon
disk is in place.
Widened holes in vial caps
Replace vial caps when holes widen and
leaks develop. (A sample with a low
boiling point can escape through a hole
that has become too large.)
Inlet pressure set too low.
Adjust the pressure.
Incorrectly placed or
missing Teflon disk on
the syringe needle
Check every syringe needle to make
sure the Teflon disk is present and
correctly placed.
Maintenance and Troubleshooting 7-5
Safety Shutdown
Programmable cool on-column inlets that are equipped with electronic pressure control have a
safety shutdown feature to prevent gas leaks from creating a safety hazard. If the system
cannot reach a pressure setpoint, the system beeps. After about two minutes, the beeping stops
and the following message appears on the display:
ACTUAL
SETPOINT
SHUTDOWN
Also, a relay signal is set that can trigger an alarm.
A safety shutdown can occur under the following conditions:
1. There is a leak in the system (see "Pressure and Temperature Control Problems"). This
includes missing septa or columns!
2. The column is not restrictive enough to reach desired pressure (i.e., 530 \i columns will
not go to 100 psi with available flow).
Note: This may occur during a programmed pressure ramp that is too high a pressure.
3. There is insufficient supply pressure.
4. Configuration is set wrong. Check the mode switch on the inlet controller board (see
"Proper Configuration").
To recover from a safety shutdown, turn the GC power off, then on. Then reset temperature
and pressure zones to desired values. (After safety shutdown, pressure setpoint is automatically
reset to zero.)
Maintenance and Troubleshooting 7-6
Septum Problems
The od and thickness of the disk septa are critical for long life and leak-free operation. If the
od is too small and the septum is too thick, the septum will fail prematurely. A thick septum can
bend needles and make needle insertion difficult.
If the septum drops easily into the retaining well and falls out when the needle guide is turned
upright, the od is too small. The od should be 5 mm, and the septum should fit snugly in the
retaining well.
When the needle guide is screwed onto the inlet, resistance will be felt when contact is made
with the septum. This should occur when the guide is 1/8-or 1/4-tum from bottoming on the
inlet body. If contact occurs sooner, the septum is too thick. If no resistance is felt, the septum
may be too thin.
Maintenance and Troubleshooting 7-7
Syringe Problems
For manual injection with fused silica needles, make sure the needle is clean and free of dust.
Wipe with solvent wet tissue, and wipe dry just before injection. Use the same solvent used to
dissolve the sample. If the needle should break, replace it. Do not use a needle less than 10 cm
long.
For automatic injection, the same cleanliness precautions apply as mentioned earlier. All the
areas in the automatic sampler that introduce samples (wash/waste bottles, needle guide)
collect dust and should be cleaned periodically.
For longer septum life, you can polish the syringe needle with fine abrasive to remove any
concentric ridges left from the needle drawing process. These are visible when magnified,
and, if present, can scrape septum particles into the inlet.
Maintenance and Troubleshooting 7-8
Automatic Sampler Vial Cap Septum Problems
Contamination can occur from vial cap septa, particularly if more than three injections are
made from one vial. Repeated punctures may dislodge septum pieces into the sample. To
determine if this is a contamination source, cut a 1- x 2-mm segment from a septum and slurry
in a vial with 1 ml of the same solvent used for the sample. Analyze this mixture under the same
conditions used for sample analysis. If peaks appear that might interfere with your analysis, try
other types of septa until you find one compatible with your analysis. A similar test can be run
with the injection port septum if you suspect it to be a source of contamination.
Contamination can also occur when small particles are picked up by the sampler syringe and
delivered on column. The symptom is sudden onset of a tailing solvent and early eluting
component peaks.
The only solution is to remove enough column to eliminate the particles. The easiest way to
find them is to backlight the column with a flashlight. Cover the lens with a tissue to diffuse the
light. Move the light along the column until the offending particles are found and cut off
enough column to eliminate them. Use a magnifier if necessary; a single, very small particle will
cause significant tailing.
Maintenance and Troubleshooting 7-9
FID Flameout Problems
When using pressure programming with large id columns (i.e., 530 \i columns) it is possible to
blow out the FID flame if pressure (flow) becomes too high. If this occurs, either lower the
pressure ramp or switch to a more restrictive column (longer and/or smaller id).
Maintenance and Troubleshooting 7-10
Peak Broadening and Split Peaks
As a sample is injected on the column at a temperature below the boiling point of the solvent,
the carrier gas pushes the liquid farther into the column, creating a flooded zone. The solute
components are spread over the length of the flooded zone. This is called band broadening in
space.
1 . Sample on column at moment of injection
2 . Carrier gas pushes liquid solvent to create a
flooded zone. The solutes distribute themselves
evenly across this zone, causing band broadening.
The flooded zone is made worse when the solvent
is less soluble in the stationary phase.
The length of the flooded zone depends on the solubility of the solvent in the stationary phase.
If the solvent is less soluble, the flooded zone will be longer, and peak broadening will be
greater.
Further distortion comes from nonuniform distribution of low volatility compounds across the
solvent band. This gets worse as sample volume increases, and column length or diameter
decreases.
Maintenance and Troubleshooting 7-11
Possible Solutions
1. Check Solubilities.
Make sure the polarity of the solvent is compatible with with polarity of the stationary phase
you are using. The length of the flooded zone is affected by the solubility of the solvent in the
stationary phase. If the solvent is less soluble, the flooded zone will be longer, and peak
broadening will be greater.
2. Use a Retention Gap (RG).
A retention gap is a deactivated, uncoated (or thinly coated) precolumn in series with the
analytical column.
In general, the length of the retention gap required and type of deactivation depend on
injected volume and solvent polarity. A working rule of thumb is to use 0.3-m or 1-m of
retention gap per |xl injected. For a 3 |xl sample, use a 3-m RG. The RG should be wetted by the
solvent, which means it should be deactivated with material of like polarity. Fused silica tubing
is commercially available in a range of diameters and deactivations.
Automatic injection requires a 0.53-mm id RG, but the analytical column can be of smaller id.
3. Optimize the Temperature Program and Inlet.
Check the boiling points of the solvent and solutes.
4. Use the Right Injection Volume.
Know the capacity of the column. Injection volume is important; large volumes may exhibit
band broadening, particularly for components whose boiling points are more than 150 °C above
that of the solvent.
Maintenance and Troubleshooting 7-12
Proper Configuration
If the inlet is not working at all, there may be a configuration problem.
1. Turn off the GC power, and remove the side panel of the GC.
2. Check if the switches on the inlet controller board are set for your configuration.
3. Turn on the GC.
Maintenance and Troubleshooting 7-13
Switch Setting Examples
INLET B = Cool On-Column with Electronic Pressure Control
INLET A = Any Non-Electronic Pressure Controlled Inlet
r
i !
i
Left = Open
Right = Closed
INB1
•RIGHT
IN BO
LEFT
MODEB
LEFT
INA1
RIGHT
INAO
-•.RIGHT
•*-;
MODE A
*"'
RIGHT
NOTE
This group ol switches controls the A position
inlet. If another electronic pressure controlled
inlet is installed in the A position, this group of
switches must be set according to the
instructions for that particular inlet.
INLET B = Any Non-Electronic Pressure Controlled Inlet
INLET A = Cool On-Column with Electronic Pressure Control
Left = Open
Right = Closed
r
iv.viv:
...vt.v
pvt:
INB1
RIGHT
IN BO
RIGHT
MODEB
RIGHT
INA1
-
RIGHT
INAO •«-
LEFT
MODE A
LEFT
Maintenance and Troubleshooting 7 - 1 4
NOTE
This group of switches controls the B position
inlet. If another electronic pressure controlled
inlet is installed in the A position, this group of
switches must be set according to the
instructions for that particular inlet.
INLET B = Cool On-Column with Electronic Pressure Control
INLET A = Cool On-Column with Electronic Pressure Control
Left = Open
Right = Closed
.... I,.,
i
1 1
L.
)
1 1
L
L.
INB1
BRIGHT
IN BO *
LEFT
MODE B «•
LEFT
INA1
P-RIGHT
INAO -•
LEFT
MODE A -*
LEFT
Maintenance and Troubleshooting 7-15
INLET B = Cool On-Column with Manual Pressure Control
INLET A = Any Other Inlet
Left = Open
Right = Closed
1
INB1
IN BO ••
I
RIGHT
*• RIGHT
LEFT
INA1
•* RIGHT
INAO
»- RIGHT
INLET B = Any Other Inlet
INLET A = Cool On-Column with Manual Pressure Control
I
Left = Open
Right = Closed
n
i.
y.y.'.r.y.
•*» RIGHT
IN B1
•« RIGHT
IN BO
»> RIGHT
INA1
BRIGHT
:::::£:::
C
IN AO •*
LEFT
Maintenance and Troubleshooting 7-16
INLET B = Cool On-Column with Manual Pressure Control
INLET A = Cool On-Column with Manual Pressure Control
Left = Open
Right = Closed
.\
1 . 1
m1 1
I
|
c
I
• * - RIGHT
INB1
- • * RIGHT
IN BO
— LEFT
INA1
- P . RIGHT
INAO
-
LEFT
Maintenance and Troubleshooting 7-17
Useful Tools
• Ultrasonic Cleaning Bath - It is the only effective way to clean small parts.
• Tungsten Carbide Knife - Used for cutting fused silica tubing. The knife edge can
be kept sharp with an inexpensive diamond hone, such as those used for touching up
carbide-tipped saw blades and router tips.
• Drill Index (#61 -80) - Used for drilling holes in Vespel and Graphite/Vespel ferrules.
• Reamers - Used to ream slightly undersized holes drilled in ferrules to match column
diameter closely.
• 10x Magnifier - Used for examination of column ends and small hardware.
• Hemostats (curved or straight) - Very handy for manipulating small parts without losing
them or contaminating with fingerprints.
• Fine Abrasive Paper (emery or 600-grit silicon carbide) - Used for smoothing rough
edges and polishing surfaces.
Maintenance and Troubleshooting 7-18
Index
250 urn injection, 6-8, 6-9
320 |xm injection, 6-8, 6-9
preparing, 3-8
sizes of, 3-1
column length, corrected, 4-12
column size, checking the, 3-3
configuring the system, 7-13
automated injection
consumables, 2-4
guidelines, 6-2
installing the column, 3-8
installing the syringe, 3-7, 6-11
vial cap problems, 7-9
automatic injection, 6-7
average linear velocity, setting, 4-16
constant flow, turning off, 4-9
constant flow modes, 4-8
constant pressure, 4-6
cool on—column, defining, 1-1
cool on—column features, 1-2, 1-3
cryo blast, 5-4
cryogenic oven cooling, 5-3
B
band broadening in space, 7-11
butt connectors, 2-6
electronic pressure programming, 4setting constant, 4-6
setting switches, 7-14
capillary columns, preparing, 3-2
ferrules, 3-10
cleaning and care, 7-2
FID flameout problems, 7-10
cleaning the system, 7-2
flooded zone, 7-11
column
connecting, 3-2, 3-8
installation problems, 3-10
installing, 3-8
flow control modes, 4-8
bent needles, troubleshooting, 7-4
flow programs, setting, 4-14
flow rate, setting, 4-10
Index 1
I
injection
automated, 6-8, 6-9
automatic, 6-7
manual, 6-3, 6-4
injections, 6-1
inlet septum nut, aligning, 3-6
inlet switches, setting, 7-14
inlet temperature
programs, 5-2
setting, 5-1
setting oven track, 5-2
insert, 1-1, 3-3
changing, 3-4
cleaning, 7-2
installing, 3-4
selecting the correct, 2-2
linear velocity, 4-2
setting, 4-16
low pressure, 7-3
M
maintenance, 7-1
manual injection, 6-3
manual pressure control, 4-18
setting switches, 7-16
mass flow rate, setting, 4-10
N
needle, replacing the universal syringe, 6-6
needle guide, 2-4
changing, 2-3
Index 2
cleaning, 7-2
needle size, 3-3
needle support assembly, 6-9
250 \im columns, 2-4
320 \im columns, 2-4
selecting, 2-4
needle—to—column size, 3-3
needles
fused silica, 6-4
replacing fused silica, 6-5
stainless steel, 6-3
not ready light, 7-3
oven, cryogenic cooling, 5-3
peak broadening, 7-11
poor precision, 7-5
precolumn, using, 2-5
press-fit connectors, 2-5
pressure
choosing best, 4-2
setting, 4-1
setting constant, 4-6
setting manually, 4-18
setting programs, 4-6
setting with electronic pressure
programming, 4-4
too low, 7-3
zeroing, 4-5
pressure gauge, 4-18
pressure regulator, 4-18
pressure units, selecting, 4-4
program, flow, 4-14
programmed pressure, 4-6
programmed temperature, 5-2
purged connectors, 2-6
syringe needle
aligning, 3-6
installing into the syringe barrel, 3-7
syringe problems, 7-8
R
retention gap, 7-12
using, 2-5
safety shutdown, 4-3
electronic control, 7-6
selecting pressure units, 4-4
septum, changing, 2-3
septum nut, aligning, 3-6
temperature
guidelines for selecting, 5-1
inlet programs, 5-2
oven track, 5-2
setting, 5-1
tools, 7-18
troubleshooting, 7-1
automated injection, 7-3
manual injection, 7-3
septum, 7-7
septum problems, 7-7
split peaks, 7-11
syringe
automated injection, 6-12
installing for automated injection, 6-11
replacing the universal, 6-6
V
vacuum compensation, using, 4-17
vent flow rate, 4-3
vial cap septum problems, 7-9
Index 3
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