8/3/2019 D02507~
1/1
IN BRIEF
Identification of molecular organic and inorganic materials
Powerful tool for polymers and rubbers, including deformulation
and kinetics
Infrared microscopy for mapping and analysis to below 5 micron
size resolution
Simple analysis through ATR
Excellent tools for mixture analysis
Non-destructive, often non-contact analysis
Heavily used in quality control/quality assurance settings
Applications
FT-IR spectra reveal the composition of solids, liquids and
gases.
The most common use is in identification of unknown
materials
and confirmation of production materials (incoming or
outgoing).
The information content is very specific in most cases,
permitting
fine discrimination between like materials. The speed of
analysis
makes it particularly useful in screening applications, while
the
sensitivity empowers many advanced research applications.
The
total scope of FT-IR applications is extensive. Some of the
more
common applications are:
Incoming materials/outgoing materials quality verification
Deformulation of polymers, rubbers and other materialsthrough
TGA-IR or GC-IR
Analysis of small sections of materials using microscopy,to
identify contaminants
Analysis of thin films and coatings
Automotive or smokestack emissions monitoring
Failure analysis
As an example, on an automobile, a huge number of components
are susceptible to FT-IR analysis: epoxies, oil coatings on
parts, fuel, rubber seals and o-rings, tires, paints, fabrics
(flame
retardants) and exhaust emissions, to name a few.
Basic TheoryMolecules that have a change in dipole moment when
they vibrate absorb infrare
radiation. This absorption is indicated by peaks in the
spectrum, with the peaks
being specific for the type of vibration. Thus, alcohols look
different from ketones,
and esters from ethers. This is the source of the identification
power of Infrared
spectroscopy. Fourier transform (FT) relates to a mathematic way
to convert rapid
collected time domain data to spectra that we can interpret. The
combination of
computers and interferometry supply the power of FT-IR.
When configuring an FT-IR spectrometer, it is important to
define the specific
target. Most users operate in the mid-IR where the majority of
the absorption
bands appear. Some users select near-IR for the ease of
sampling, although some
information is lost, or far-IR when inorganic species are
involved. In each case, th
spectrometer components need to be properly selected a
combination of source
beam splitters and detectors. The size (intensity) of the
absorptions depends upon
several factors, but particularly useful information is
concentration such that FT-IR
can be used in quantitative analyses.
The FT spectrometer works by splitting an IR beam into two. When
these
recombine, the light waves interfere constructively or
destructively, creating the
interferogram which is the time domain signal. The transform
converts this to a
spectrum that can be interpreted.
A common sampling technique is ATR, or attenuated total
reflectance. Samp
are placed on a crystal; the IR light hits the back of the
crystal and absorption
occurs on the surface. This is easy, fast and requires minimal
sample preparation
Technology
FT-IR is very fast spectra can be collected in seconds, and a
library search provid
immediate identification. In less than a minute, you go from an
unknown to a know
identity. With ATR, you can process raw samples. The entire
spectrum is collected
once, and you can co-add spectra to improve the signal to noise
ratio. Dynamic
alignment allows the instrument to be used in noisy
environments, and sealingkeeps out dust. FT-IR is one of the most
common analysis tools used in laboratori
world wide.
For more information go to
www.thermoscientific.com/MaterialsScience
OV52136_E 05/11M 2011 Thermo Fisher Scientific Inc. All rights
reserved.
Q U I C K G U I D E
FT-IR Spectroscopy
Thermo Scientific Products:
Nicolet iS5 FT-IR Spectrometer
Nicolet iS10 FT-IR Spectrometer
Nicolet 6700 FT-IR Spectrometer
Nicolet 8700 FT-IR Spectrometer
Nicolet Continum Microscope
Nicolet iN10/iN10MX FT-IR Microscope
