5991 1840EN

5991 1840EN
Agilent 7890B/5977A GC/MSD
Integrated Intelligence Boosts
Productivity and Lowers Cost of
Operation
Technical Overview
Introduction
The Agilent GC/MSD system has long been a mainstay productivity tool in laboratories performing environmental, forensic toxicology, food, fine chemical, and other
analyses. Each generation of the system has improved the data quality, sensitivity,
ease-of-use and cost of operation, helping laboratory managers meet their
performance goals during challenging economic times.
The Agilent 6890 Gas Chromatograph, which was released in 1995, was the first GC to
offer a Gas Saver function to reduce the gas consumption using electronic pneumatic
control (EPC). It also featured a GC Method Translator for method optimization when
using new column technology. The Agilent 5973 GC/MSD, introduced in 1996, featured Early Maintenance Feedback (EMF), which assured optimal maintenance to
preserve data quality.
The Integrated Intelligence of the Agilent 7890B/5977A GC/MSD system simplifies
and improves the use of Gas Saver, GC Method Translator and EMF, and it adds two
features to boost productivity: Sleep/Wake mode and Fast Vent. This technical
overview introduces those new features and reviews the improved existing features.
Figure 1.
The Agilent 7890B/5977A GC/MSD System.
Sleep/Wake Mode
The new Sleep/Wake feature of the 7890B/5977A GC/MSD
automates the setting of the system’s sleep and wake parameters and reduces power and gas usage. The Sleep/Wake
method is initiated from the MSD software or the GC panel
(Figures 2 and 3). During routine use, the sleep and wake times
can be set in the Scheduler (Figure 4). Additionally, the sleepmode can be initiated directly from the sequence table
(Figure 5). This is accomplished by simply adding the keyword
at the end of the sequence. The system will then enter Sleep
mode at the completion of the sequence, thus saving on power
and gas consumption.
Figure 2.
Accessing the Sleep/Wake feature from
the instrument menu.
Figure 3.
Figure 4.
Setting the Sleep/Wake parameters in the Instrument Schedule screen.
Figure 5.
Using the Sleep keyword in the Sequence Table of MassHunter Software.
2
The Sleep/Wake schedule screen on
the Agilent 7890B GC panel.
Fast Vent
Early Maintenance Feedback (EMF)
The 5977A GC/MSD is the only system that heats the quadrupole to temperatures above 100°C (typically to 150–200 °C) to
rapidly eliminate any contamination in the analyzer. This high
temperature design assures rapid startup, by eliminating background noise from moisture, and assures robust and reliable
results over many injections by eliminating contamination by
high boiling compounds.
Regular maintenance is a key factor for optimal GC/MS results.
While EMF has been part of the Agilent GC/MSD system for
many years, it has now been completely redesigned and is fully
integrated into the 7890B/5977A GC/MSD system. Using the
EMF screen (Figure 6), an operator can quickly manage limits
and service due dates. This screen also displays important
parameters such as the number of injections since the last
maintenance and the elapsed time since the last source cleaning. The status of GC and MSD consumables, including the
inlet liner, filaments, and the pump oil, is also tracked in EMF.
Additional user-defined counters can be configured as well.
Deviations from the set parameters will create an alert and
comment in the EMF log file, providing a history of the instrument status. The newly integrated EMF is an excellent tool to
prevent major maintenance issues and reduce downtime.
The heated source and quadrupole must be cooled before
maintenance can begin in order to prevent oxidization of the ion
source, and this can add as much as 30 to 40 minutes to the
time required to perform maintenance. The new Fast Vent feature reduces the time for cooling the MSD up to 40% by directly
communicating with the GC to enter MSD Vent mode.
Figure 6.
EMF (Early Maintenance Feedback) screen.
3
GC Method Translator
an analysis can be improved if a smaller diameter column (such
as 0.18 mm) is used while maintaining the same run time as
the larger diameter. If faster chromatography is desirable, the
analysis time can be shortened while maintaining the same
resolution as the larger bore column. The built-in translator
optimizes the method based on which outcome is specified,
higher resolution or faster run-time.
This feature is now fully integrated into the 7890B software
(Figure 7). It facilitates the optimized translation of a method to
alternative column dimensions or carrier gas. The translator will
automatically update the method with the new optimized
parameters with the simple click of a button.
The optimal fused-silica column dimensions for GC/MS are
dependent on the particular application being run. The most
common length and inner diameter for GC/MS are 30 meters
and 0.25 mm respectively. The chromatographic resolution of
Figure 7.
Additionally, there is often a significant difference in sample
capacity between a conventional column and a narrow bore
column, and the new translator helps identify these cases, so
that any capacity problems can be avoided.
The GC Method Translator screen.
4
Gas Saver
Guidelines for optimal use of the Gas Saver are easy to follow:
The 7890 GC Gas Saver feature, which was introduced with the
6890 GC, is specified as part of the method. The basic purpose
is to reduce the purge flow (Splitless Injection) or the split flow
(Split Injection) during data acquisition, thus reducing gas
usage. The optimum flow depends on the column flow mode,
(e.g., Constant Flow/Pressure Mode, Ramp Flow/Pressure
Mode), column oven temperature program (Final Oven Temp),
and the column dimensions (Table 1).
•
The lowest Gas Saver flow setting may cause inlet pressure (or flow) shutdown due to insufficient gas flow to the
inlet. In order to properly optimize the Gas Saver flow, it is
necessary to run the method and confirm the flow and
pressure stability of the inlet.
•
The saver time must be specified in the GC inlet
settings (Figure 8).
•
If the injection mode is Splitless, the saver time should be
greater (0.2 minute or more) than the purge time.
•
If the injection mode is Split, the time required for all samples in the inlet liner to be introduced to the column must
be estimated. The approximate column introduction time
can be calculated from the Inlet liner volume and the sum
of column flow and split flow.
Table 1.
Example of Suggested Gas Saver Parameters
Without gas saver
With gas saver
Injection mode
Splitless
Splitless
Purge flow
50 mL/min at 1.5 minutes
50 mL/min at 1.5 minutes
Column flow
1 mL/min
1 mL/min
GC run time
30 minutes
30 minutes
Gas Saver
Off
On, saver flow 25 mL/min at 2minutes
Total gas consumption
1,425 mL
755 mL*
*Depending on the ion source temperature, quadrupole temperature and MSD Vent method settings
Figure 8.
Gas saver setting screen.
5
Summary
The Integrated Intelligence of the Agilent 7890B GC and 5977A
GC/MSD has made it much easier to set up and routinely use
these energy saving, higher productivity features. Start using
Sleep/Wake, Gas Saver, Early Maintenance Feedback and Fast
Vent as soon as possible. These features will lower your cost of
operation and ensure maximum uptime for your GC or GC/MSD
system, without compromising performance.
A summary of these features, as well as additional information
regarding the use of the instrument, can also be found in
“Agilent 7890B Gas Chromatograph-Getting Started”, which is
shipped with every 7890B GC instrument.
www.agilent.com/chem
Agilent 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.
Information, descriptions, and specifications in this
publication are subject to change without notice.
© Agilent Technologies, Inc., 2013
Printed in the USA
January 31, 2013
5991-1840EN
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