FTIR, IR microscopy, and Raman
Purpose: Become familiar with the FTIR and FTIR microscopy. For the FTIR, organic solvents
will be examined and for the microscope portion, fibers will be analyzed. (Raman was down)
Background:
Fourir Transform infrared spectroscopy is generally used to probe the bond types of the
sample analyte. This technique is generally used for qualitative analysis. Using FTIR microscopy
allows us to focus the infrared bean on a very specific area of a sample, or locate and probe a
small sample. A common use of this technique is to look at fibers. The Raman uses scattered
radiation that corresponds to the vibrational modes of the molecule.
Procedures:
IR
Open Varian Resolution Pro
go to current scan at bottom > Basic IR Scan
Click on the Center burst on towards bottom of the page
Ensure the black flap on the right side of the FT-IR is pushed down
Ensure you see the center burst, and a number in the left corner ranging from 1.2-5
Check the parameters on the right side
View - Interferrogram
Aperture - 2cm-1 at 2000cm-1
Sensitivity – 1
Hit OK button
Collect > Electronics
Speed – 20 KHz
Filter – 5
UDR – 2
Resolution - 0.5
Sensitivity – 1
Scans to co add – 16
Save range – 4000-700cm-1
12. Check Parameters in Optics Tab
IR-Source – Mid-IR
Beam – internal
Detector – DTGS-Det#1
Beamsplitter – KBR Broadband
Accessory – None
Source - 2cm-1 at 2000cm-1
Microscope Box – Detector: Left, Optics Mode: Reflectance
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13. Insert blank
14. Go back to the graph in the resolutions pro program
Select the polystyrene sample graph and change the absorbance to % transmittance by
selecting “% transmittance” under the transforms menu at top
15. To Shut Down: close Varian resolutions Pro and leave everything on.
IR Microscope
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Fill the Microscope detector with liquid nitrogen
Insert ATR crystal
To set up software, open software by click ‘varian resolutons pro’
From ‘current scan’ drop down, select method file ‘microscope’
From collect menu, select rapid scan, check that parametres are set up same as above
procedure states
6. Run a background scan and then run the samples
Raman
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Fill The RAMAN blue dewar with liquid nitrogen
Make sure the FT-IR instrument is on
Top off the dewar with (l) nitrogen after 10 min
Turn on the power supply to the laser located on the floor
The two levers on either side of the Raman must be switched to on.
The lever inside the Raman should be up with the bypass closed.
Prepare sample and put solid in capillary tube to a depth of 1 inch
Center the sample on the red dot on the holographic filter, adjust X,Y, and Z knobs if needed
Open Varian Resolution Pro on the desktop.
Current Scan Menu
IR source: off
Beam: right
Detector: Raman ge
Beamsplitter: Quartz Near IR
ATR Crystal: None
Optical filter: Holographic Notch
Aperture: Open
Select laser tab click turn on diode
Press the shutter switch in front of Raman
Set the Raman power to the highest of 3
Return to software and the laser tab and adjust the value of the laser control current to 600-700
mW
Click setup and center burst should appear. Adjust X,Y,Z knobs to find center burst
16. Click scan
17. Shutting down
Turn of laser by selecting Raman scan, and laser tab click turn off diode
Press the shutter button on the front of the Raman to close the shutter
Remove the sample
Turn off laser
Do not turn off computer, FT-IR, or Raman accessory
Data:
FTIR:
Toluene
2-Propanol
2-Butanone
%
%T
%
%T
%
%T
100
40.111
0
n/a
0
n/a
0
n/a
100
20.246
0
n/a
0
n/a
0
n/a
100
0.054294
25
74.956
25
68.76
50
4.1811
25
73.473
50
44.002
25
14.052
50
59.428
25
63.664
25
18.065
33
65.393
33
58.589
33
3.9065
55.80993568
59.525
7.072249589
75.143
42.44863388
8.8219
Samples:
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2-Butanone
2-Propanol
Toluene
Mixture 1: Toluene, 2-Propanol, 2-Butanone (1:1:2)
Mixture 2: Toluene, 2-Propanol, 2-Butanone (1:2:1)
Mixture 3: Toluene, 2-Propanol, 2-Butanone (2:1:1)
Mixture 4: Toluene, 2-Propanol, 2-Butanone (1:1:1)
Unknown
Calibration Curves:
% Transmittance (%)
Toluene
80
70
60
50
40
30
20
10
0
y = -0.4399x + 83.173
R² = 0.9698
0
20
40
60
80
100
120
Mass percent (%)
2-Propanol
80
y = -0.6095x + 79.454
R² = 0.9677
% Transmittance (%)
70
60
50
40
30
20
10
0
0
20
40
60
80
Mass percent (%)
100
120
2-Butanone
%Transmittance (%)
20
15
y = -0.1833x + 16.593
R² = 0.5756
10
5
0
0
-5
20
40
60
Mass percent (%)
80
100
120
Conclusion:
We were able to get results with the FTIR and with the IR microscope. The Raman was not
working so we were not able to use it. We got good results without liquid samples on the FTIR
but we ran into a problem at the end. The library on the computer was either not working or we
were working it wrong although we followed the directions. For each sample, the library would
give us over 1,000 hits instead of narrowing it down for us. If we had an actual unknown and not
one with just unknown proportions, identifying the sample would be extremely difficult.
Looking at the calibration curves, the one for the 2-Butanone was not very good. The R2 value
was only 0.5756 which is really low. There could have been a contamination possibly between
changing out samples which could result on sample not being pure.