FTIR Spectroscopy

(Brucker Vector 22)

Warning: This instrument may only be operated by those who have been trained by AAF staff and have read and signed the AAF laboratory policies.

1.0 PURPOSE: In infrared spectroscopy, IR radiation is passed through a sample. Some of the infrared radiation is absorbed by the sample and some of it is passed through (transmitted). The resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample. An infrared spectrum represents a fingerprint of a sample with absorption peaks which correspond to the frequencies of vibrations of the atoms making up the material. Because each different material is a unique combination of atoms, no two compounds produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a positive identification (qualitative analysis) of most different kinds of material. In addition, the size of the peaks in the spectrum is a direct indication of the amount of material present and the cross section for absorption of the absorption band. With modern software algorithms, infrared can also be an excellent tool for quantitative analysis. This makes infrared spectroscopy useful for several types of analysis.

• It can identify unknown materials

• It can determine the quality or consistency of a sample

• It can determine the amount of components in a mixture

This procedure will explain the steps to use the Brucker Vector 22 to obtain FTIR information.

2.0 SAFETY CAUTIONS:

2.1 Only trained personnel are permitted to operate the FTIR instrument (EMS 1262).

2.2 The instrument needs 2 hours of warm up for the source and H

2

O-CO 2 to stabilize.

3.0 PROTECTIVE EQUIPMENT REQUIREMENTS:

3.1 Latex or Nitrile gloves when handling samples and cleaning solvents

4.0 OPERATING PROCEDURE:

4.1 Double click on the “OPUS” Icon:

4.1.1 Password: OPUS (all capital letters) (press Login)

4.1.2 Click on “OK”

4.1.3 Window list and Display Default windows appear

4.2 Check the signal strength of the instrument to verify that it is running properly, if it is out of spec contact Steve Hardcastle:

4.2.1 Click on “MEASURE” from along the top tool bar.

4.2.2 A drop down box opens, click on “Advanced Measurement”

4.2.3 Click on the “Check Signal” tab (Interferogram box checked)

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4.2.4 From the box that opens verify the following (see Steve H to change ATR attachment – use diamond crystal if possible. AMTIR and ZnSe are soft and have

PH restrictions):

4.2.4.1 OPEN PATH: ~21,000 CPS (amplitude)

4.2.4.2 AMTIR ATR: 11,000 CPS (max)

4.2.4.3 Diamond ATR: 1450 CPS (max)

4.2.4.4 ZnSe multi bounce: 2,500 cps (flat one)

4.2.4.5 ZnSe multi bounce: 1,000 cps (liquid)

4.2.4.6 Reflection (can use polarizer): (Au Mirror) 5,500 cps

4.2.4.7 Click EXIT when done

4.3 Sample Attachments are fastened via the one screw mounting plate in the middle part of the instrument. Level the mounting block screws by hand (forward right-back right-left.

Each attachment has its own leveling adjustments (ATR AMTIR-Diamond left-right screws for final signal max. If adjusting these recheck the signal of the instrument (step 4.2).

4.4 A background of the atmosphere should be run first:

4.4.1 Click on “MEASURE” from along the top tool bar.

4.4.2 A drop down box opens, click on “Advanced Measurement”

4.4.3 Enter a name in the “File Name” area of the “basic advanced” tab (for example bkgrd). Check sample scan is 100 scans

4.4.4 Click on the “Basic” tab and change the name of the sample (for example bkgrd).

4.4.5 Click on “Sample Single Channel”, this will start the FTIR running 100 scans of the atmosphere, and takes roughly 1.5 minutes.

4.4.6 When the scanning is complete, press the “display” tab, and select the Y scale to see the result.

4.5 A sample of PE is run next to verify that the instrument is not contaminated, and showing extraneous peaks:

4.5.1 Place a PE baggie on the ATR table.

4.5.2 Carefully screw down the ATR hammer, until the clutch begins to slip, and the hammer will not further tighten down.

4.5.3 Click on “MEASURE” from along the top tool bar.

4.5.4 A drop down box opens, click on “Advanced Measurement”

4.5.5 Enter a name in the “File Name” area of the first tab (for example PE bag).

4.5.6 Click on the “Basic” tab and change the name of the sample (for example PR bag).

4.5.7 Click on “Sample Single Channel”, this will start the FTIR running 100 scans of the atmosphere, and takes roughly 1.5 minutes.

4.5.8 Ratio out the atmosphere background:

4.5.8.1 Click on “MANIPULATE” from along the top tool bar.

4.5.8.2 A drop down box opens, click on “Spectrum Calculator”

4.5.8.3 Remove what is showing up on the right hand, top side of the box

by clicking on the button (top right icon).

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4.5.8.4 Add the PE sample SSC Spectrum channel by left clicking on its spectrum in the OPUS browser to the left, and dragging it into the spectrum calculator window.

4.5.8.5 Press the button.

4.5.8.6 Add the background SSC spectrum by left clicking on its spectrum in the

OPUS browser to the left, and dragging it into the spectrum calculator window.

4.5.8.7 Press the button. (A Trans or Abs scan now seen)

4.5.8.8 Verify that only the CH and CC peaks of PE are seen (see spectrum on wall). If any other peaks are seen, the instrument/ATR table is contaminated and needs to be cleaned. Once clean repeat set 4.5.

4.5.8.8.1 Two CH peaks at 2800-3000 wave numbers (cm-1)

4.5.8.8.2 One CC peak at ~1400 cm-1

4.5.8.8.3 One CH peak at ~720 cm-1

4.5.8.9 See 4.7 to see spectrum in new window

4.6 To run a sample:

4.6.1 Place a sheet of aluminum foil or weigh paper on the ATR top Hammer piece (the part that screws down onto the sample), to keep things from being contaminated.

4.6.2 Repeat steps in 4.5, with the sample to be tested.

4.7 The Opus Browser now has a single channel icon (SSC) and a transmission (TR) icon of your sample. To switch to TR viewing:

4.7.1 Select the “WINDOW” tab.

4.7.2 From the drop down box select “New Spectrum Window”

4.7.3 Click on the TR in the OPUS browser and drag it to the newly created window.

4.8 To change the view to absorbance (ABS):

4.8.1 Select the TR of the desired spectrum in the OPUS Window

4.8.2 Select the “MANIPULATE” tab

4.8.3 Select the AB TR Conversion choice.

4.9 To Zoom in on an area of the spectrum (data below 540 cm-1 is noise):

4.9.1 Left click on “DISPLAY”

4.9.2 Left click on “ZOOM IN” from the drop down box.

4.9.3 Left click and draw a box around the area of interest, release the mouse with the box is complete.

4.10 To save a result:

4.10.1 Left click on the “FILE” tab from the top.

4.10.2 Select “Save File As” from the drop down box.

4.10.3 Select the “CHANGE PATH” button

4.10.4 Select D:DATA\Data and the appropriate folder to save data to (for example

D:DATA\DATA\XYZ) New folders need to be created outside OPUS.

4.10.5 Select the “MODE” tab.

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4.10.6 Click on and verify that the extension for the OPUS format is XX.0

4.10.7 Change the name of the data to the desired name (this saves OPUS binary format). The system name can take up to 8 characters.

4.10.8 Click on the “SAVE” button.

4.10.9 Select the “MODE” tab.

4.10.10 Click on and verify that the extension for the JCAMP.DX format is XX.DX

4.10.11 Verify that the desired name is still showing. [eg type in abc123.DX]

4.10.12 Click on the “SAVE” button (go back to FILE -> Save File As).

4.10.13 Select the “MODE” tab.

4.10.14 Click on and verify that the extension for the DATA POINT TABLE format is XX.DPT

(XY pairs - ASCII).

4.10.15 Verify that the desired name is still showing.

4.10.16 Click on the “SAVE” button.

4.11 Removing Spectrum from the Opus Window, after completion:

4.11.1 Click on and highlight the spectrum in the Opus Window.

4.11.2 Left click on the “FILE” tab from the top.

4.11.3 Select “Unload File Choice” from the drop down box.

4.11.4 Click on the “UNLOAD” button to remove.

4.12 To Analyze Spectrum:

4.12.1 Open the “WINFIRST” program icon on the desktop.

4.12.2 Select “TOOLS” from the tab choices at the top.

4.12.3 Select “ADVANCED MENU” from the dropdown box.

4.12.4 In the field that opens up, enter the password of “WINFIRST” then press ok.

4.12.5 Select “FILE” from the tab choices at the top.

4.12.6 Select “Load Sample” from the drop down choices:

4.12.6.1 There are several choices of what type of file that can be loaded, select the JCAMP.DX file.

4.12.6.2 Under “Directories” open up the location where the files were stored (for example D:DATA\DATA\JCI.

4.12.6.3 Select the desired file and press the “OK” button.

4.12.7 Manipulating this spectrum:

4.12.7.1 To truncate the spectrum:

4.12.7.1.1 Select the “MATH” tab.

4.12.7.1.2

4.12.7.1.3

Select “MORE” from the drop down box.

Select “TRUNCATE

4.12.7.2

4.12.7.1.4

4.12.7.1.5

4.12.7.1.6

Change the lower wave numbers box to 550 or 600

Press OK

Change display limits (Display-Data Area )

To Smooth the Baseline : (remember Abs peaks up Trans peaks down)

4.12.7.2.1

4.12.7.2.2

Select the “MATH” tab.

Select “Baseline” from the drop down box.

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4.12.7.3

4.12.7.2.3

4.12.7.2.4

Left click at each wanted baseline point. This can be clicked as often as wanted to help with smoothing.

When the desired points have been clicked, press the OK button.

4.12.7.2.5 Repeat as necessary.

To remove extra peaks from the atmosphere subtraction:

4.12.7.3.1

4.12.7.3.2

4.12.7.3.3

Select the “MATH” tab.

Select “MORE” from the drop down box.

Select “Line Out”. This removes the peaks and leaves a straight line (between ~2240 and 1930 cm-1).

4.12.8 Library Search:

4.12.8.1

4.12.8.2

4.12.8.3

4.12.8.4

Database Tab – Search Library (choose appropriate libraries) OK

R or R (buttons top right) to toggle through matches.

In separate new window, WinFirst shows a report of all matches

Icon left of R allows user to pick match to be display. Pick any

4.12.8.5 Print data matches Plot (F7) pdf factory

4.12.9 To Help Identify peak correlations

4.12.9.1

4.12.9.2

Double click IR MENTOR PRO program icon (desktop)

Open spectrum

4.12.9.3

4.12.9.4

Double click on a peak of interest.

Possible correlation of peak(s) will appear.

4.12.9.5 peaks

Compare intensity and locations of other peaks in same family of

4.12.10 To help with labeling peaks of the spectrum:

4.12.10.1 In WinFirst, Math, Peaks (Locator-Regression, Filter-cubic Spline,

4.12.10.2

Sensitity-3 {small peaks may not be found})

Edit peak labels location/value, Click edit annotation button in

4.12.10.3

4.12.10.4

4.12.10.5

Notate Window {upper right green pencil}

Change XY settings Display Data Area change XY fieild

Draw line to label peak functional group Click Annotate a data peak button in Notate Window. Drag line, edit text value to label

“functional” group of peak.

Save annotations by “Save Sample As” in Mattson Data File (ABSabsorption, or RAS – transmittance) If saved in DX format annotations are not saved.

4.12.11 To obtain a Plot of the spectrum:

4.12.11.1

4.12.11.2

4.12.11.3

Select the “FILE” tab.

Select “PLOT” from the drop down file.

Select the “PLOT” button, and a PDF (pdf factory) will be created of the current manipulated spectrum.

4.13 Cleaning up Sample/Instrument:

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4.13.1 Carefully unscrew and open the ATR hammer pin.

4.13.2 Remove the sample from the ATR plate, while carefully holding the base.

4.13.3 Clean the base by dampening a cloth with Isopropyl Alcohol or Ethyl Alcohol and carefully cleaning off any residue from the ATR crystal and table.

4.13.4 When clean, wipe down the ATR crystal with Glycol optic lens cleaner.

4.13.5 Verify that the instrument has been cleaned completely:

4.13.5.1 Click on “MEASURE” from along the top tool bar.

4.13.5.2

4.13.5.3

A drop down box opens, click on “Advanced Measurement”

Enter a name in the “File Name” area of the first tab (for example

4.13.5.4 bkgrd2).

Click on the “Basic” tab and change the name of the sample (for example bkgrd2).

4.13.5.5

4.13.5.6

Click on “Sample Single Channel”, this will start the FTIR running

100 scans of the atmosphere, and takes roughly 1.5 minute.

When the scanning is complete, overlay this background spectrum with the original one (can drag them both into a new window if that is helpful). Verify the overlap does not show any extra peaks. If extra peaks seen, re-clean ATR crystal.

4.14 Remove all spectrums from the Opus Window:

4.14.1 Click on and highlight a spectrum in the Opus Window.

4.14.2 Left click on the “FILE” tab from the top.

4.14.3 Select “Unload File Choice” from the drop down box.

4.14.4 Click on the “UNLOAD” button to remove.

4.14.5 Repeat until all spectrums have been removed.

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