Tim Abell
IR and IR Microscopy
Introduction
Fourier Transform Infrared Spectroscopy (FTIR) uses light in the infrared range to determine the
functional groups of a sample. Each functional group emits a unique wavelength when exposed to
infrared light. The IR microscope works in a similar way to the FTIR but is used to identify what fabrics
are made up of.
Purpose
The purpose of this lab is to run both known and unknown samples on the FTIR and the IR Microscope.
The spectra then were interpreted. Three organic solvents were run on the FTIR and fabric ssamples
were looked at on the IR Microscope.
Method
IR
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Make sure than the instrument is on.
Make sure that the black lever between the FT-IR and the Raman is down
Double click on the Varian Resolutions Pro icon in the top right of the display.
In the Current scan menu on the bottom of the screen select IR scan.
From the Collect menu at the top of the screen select Rapid scan
The Electronics tab parameters should be:
 speed: 20 KHz
 Filter: 5
 UDR: 2
The Optics tab parameters should by:
 IR Source: Mid-IR
 Beam: internal
 Detector: DTGS
 Beamsplitter: KBr Broadband
 Accessory: none
 Optical filter: none
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Aperture: 4 cm-1 at 2000 cm-1
Click setup. The voltage reading should be between 1-5V. If not, change the selectivity
Click background to run a background scan
Return to rapid scan from the collect menu and click scan
 The transformers menu allows you to convert to %T
To shut down, close Varian Resolutions Pro and LEAVE EVERYTHING ON
IR-microscope
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Fill microscope with liquid nitrogen
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Instrument is full when liquid nitrogen comes out side of funnel’s black tube
Let instrument stabilize for 15 minutes
ATR crystal is located in Varian FTIR drawer
Remove red cap from crystal
Make sure notes are facing left, and slide crystal into microscope barrel, you should hear 2 clicks
The black lever should be up between the IR and Raman, and between the Raman and IR
microscope
Open Raman lid, push the black lever in the back right corner down (set to Bypass Open) and
close lid
On the Raman instrument control panel (on front of instrument), set button to Bypass
On microscope turn up brightness, using switch
Open up Varian Resolution Pro program
From drop down menu with Current Scan, select Microscope
From Collect menu, select Rapid Scan, Under Electronics tab set parameters:
o Speed: 20KHz
o Filter: 5
o UDR: 2
o Save Range: 4000-700cm-1
Under Optics tab, set parameters
o IR Source: Mid-IR
o Beam: Right
o Detector: UMA600MCT
o Beamsplitter: KBr Broadband
o Accessory: UMA-600
o ATR Crystal: Germanium
o Optical Filter: None
o Source: Open
o Detector: Right
o Optics Mode: Reflectance
Click Setup
Center burst should appear with voltage reading between 1.5-5 (if not adjust sensitivity), click
OK
Collecting Background, put nothing under scope
From Collect Menu, select Rapid Scan > Setup
A center burst should appear, click Background
Load sample on gold plate
From Collect menu, select Rapid Scan, and click Setup
A center burst should appear
In View menu (right hand side of screen) select Processed
Carefully raise stage using Course adjustment knob until you feel minimal pressure on sample
and slide
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IR spectrum should appear on screen, use fine adjustment knob to maximize signal
Click scan to collect spectrum, graph should be in % Transmittance
To shut down, turn down brightness on microscope, take out crystal and put red cap back on,
and put in drawer. Put gold plate in drawer, put levers back and turn off bypass button.
Close Varian Resolution Pro program
The Raman was not working during the week of doing this lab, so we do not have a procedure or data
for that instrument.
Data
All spectra are attached in my notebook p. 18
Results
After analyzing known organic solvents on the FTIR we looked at two unknowns. The unknowns were
just a mixture of the two knowns in different proportions. The first unknown was one part 2-propanol
and two parts 2-butanone, a 1:2 ratio. Unknown 2 had a ratio of 1:1.
We analyzed a few known samples on the IR Microscope but did not have time to analyze and unknown
samples.
Conclusion
The instruments were pretty easy to use even the SOP was not very clear. All spectra that were obtained
were easy to interpret and understand. There were a few problems with the lab. There was no student
SOP online so we had to use then one in the lab. The other problem was that the Raman laser was not
working so we did not get to analyze any samples using it.