Brittany Hicks
FTIR & Raman Lab- Dr. Foy
Spring 2013
FTIR and Raman
Introduction
Fourier transform infrared spectroscopy is a fairly recent instrument that collects data from an
inference pattern to a spectrum. Data is continuously collected and concerted from a spectrum with a
wide range. FTIR uses a beam that contains multiple frequencies of light to measure how much of the
light is absorbed from the beam by the sample. FTIR can identify unknown materials to determine the
quality and components of a mixture within a desired sample. This procedure can reveal quantitative
and qualitative measurements.
Raman spectroscopy is a spectroscopic technique to look at frequency modes of vibrational and
rotational systems. Vibrational information relates specifically to bonds and symmetry within molecules.
The molecule can ultimately be defined through these vibrational modes. Solid, liquid and gaseous
samples can all be analyzed quantitatively and qualitatively through Raman spectroscopy.
The purpose of this experiment is to first familiarize ourselves with the instruments in ultimately
learning how to analyze and operate these instruments. Data will be collected and analyzed with the
help of a calibration curve.
Procedure - FT-IR
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Need to install IR part first
Open Varian Resolution Pro
Then 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
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Sensitivity – 1
Scans to co add – 16
Save range – 4000-700cm-1
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
Insert blank
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
FT-IR with Microscope Procedure
*** Referred to SOP located within the lab drawer.
Procedure - Varian FT-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
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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
Click scan
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 Collected
Below are calibration curves for some of the known samples recorded. All other data recorded
by the FT-IR is located in my notebook. All the spectra for the samples run are included in my notebook
to show further analysis.
Toluene
29.5
% Transmittance
27.5
25.5
23.5
21.5
19.5
20.5
25.5
30.5
35.5
40.5
Concentration (%)
45.5
50.5
2-Butanone
20
% Transmittance
18
16
14
12
10
8
20
25
30
35
Concentration (%)
40
45
50
40
45
50
2-Propanol
98
% Transmittance
93
88
83
78
73
68
20
25
30
35
Concentration (%)
For the IR- Microscope, a total of 10 samples were analyzed plus an additional background scan
to set as a baseline spectra for all other additional samples. Unknown fibers were compared to the
known spectrum to look at similarities among peaks.
*** All spectra are located within my lab notebook
The Raman instrument was down and unfortunately we did not get the opportunity to use this
instrument for analysis.
Conclusion
The FT-IR and IR-Microscope were very easy to use and actually quite interesting when analyzing
data. For the FT-IR, we were able to obtain very good results for three known organic samples:
Propanol, Butanone, and Toluene. The unknown samples ran had very similar peaks to these known
samples which suggests they are comprised of similar components within their structures.
The IR microscope was also very easy to use and produced great results. We analyzed 10
different fiber samples under the microscope. The unknown samples were compared to the spectra of
the 8 known fibers ran. Unknown C had similar wavelength and transmittance to the fiber polyester
sample. Unknown B looked similar to the PVC sample we recovered from the microscope. Overall this
lab was fun and was more relatable to my interest as a biologist.