 |
 |
& Attenuated Total Reflectance (ATR)
Technique:
FTIR is an instrument, used for identifying the chemical composition of an unknown sample using a beam of light in a non-destructive manner. ATR is a device, placed in the beam path, designed to bounce the beam off the surface of a test sample.
Application:
This technique measures the various infrared light wavelengths, absorbed by the material of interest then comparing the results to a database of known compounds. FTIR is commonly used to identify chemicals in paints, polymers and coatings. It is used to quickly identify unknown contaminants in a variety of source materials. Sensitive enough to identify different layers of paint within a single paint chip.
The Science Behind:
The infrared region of the electro-magnetic spectrum is classically defined as the wavelength region between .78 μm and 300 μm. Molecular vibration and rotation absorption are characteristic of this region. The energy of molecular rotation and vibration are controlled by the bond strength and the mass of the atoms. Strong bonds and low mass absorb at higher energy, while bonds involving heavy atoms, or groups of atoms, will absorb at lower energy (longer wavelengths). This produces a form of unique identification for many substances.
Other Resources:
Wikipedia Definition of Fourier Transform Spectroscopy
Wikipedia Definition of Infrared Spectroscopy
Excellent FTIR e-Site
Far IR - Part of the electro- magnetic spectrum. Far IR ranges from 30 micrometers (mm) to 300 mm.
Fourier Transform - Is a mathematical technique where spectra (data) are analyzed by conversion from a time domain to a frequency domain.
Infrared - Part of the electro- magnetic spectrum. IR stands for infrared or below red, a section of the electromagnetic spectrum including Near IR, IR and Far IR.
IR - Since the 1930's IR has been one of the most useful and reliable investigation tools. IR ranges from 3.0 mm to 30 mm.
Near IR - Part of the electro- magnetic spectrum. Near IR ranges from about .78 mm to 3.0 mm.
Non-Destructive - Most testing involves the removal of a small portion from the original and destroying it to get the results. In non-destructive testing the original sample remains unchanged throughout the testing process.
Spectroscopy - Is the study of matter by using the radiation emitted, adsorbed or scattered by the sample under investigation.
Fourier Transform - Is a mathematical technique where spectra (data) are analyzed by conversion from a time domain to a frequency domain.
Infrared - Part of the electro- magnetic spectrum. IR stands for infrared or below red, a section of the electromagnetic spectrum including Near IR, IR and Far IR.
IR - Since the 1930's IR has been one of the most useful and reliable investigation tools. IR ranges from 3.0 mm to 30 mm.
Near IR - Part of the electro- magnetic spectrum. Near IR ranges from about .78 mm to 3.0 mm.
Non-Destructive - Most testing involves the removal of a small portion from the original and destroying it to get the results. In non-destructive testing the original sample remains unchanged throughout the testing process.
Spectroscopy - Is the study of matter by using the radiation emitted, adsorbed or scattered by the sample under investigation.