Fourier Transform Infrared Spectroscopy (FTIR) is an analytical technique used to identify organic (and in some cases inorganic) materials. This technique measures the absorption of various infrared light wavelengths by the material of interest. These infrared absorption bands identify specific molecular components and structures.

Absorption bands in the range of 4000 - 1500 wavenumbers are typically due to functional groups (e.g. -OH, C=O, N-H, CH3, etc.). The region between 1500 - 400 wavenumbers is referred to as the fingerprint region. Absorption bands in this region are generally due to intra-molecular phenomena, and are highly specific for each material. The specificity of these bands allow computerized data searches to be performed against reference libraries to identify a material.

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Material Identification - The unknown IR absorption spectrum is compared with standard spectra in computer databases or a spectrum obtained from a know material to determine the identity of the material being analyzed. Matches identify the polymer or other organic constituent(s) in the sample.

Quantification - Quantitative concentration of a compound can be determined from the area under the curve in characteristic regions of the IR spectrum. Concentration calibration is obtained by establishing a standard curve from spectra for samples of known concentrations.

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• Identifying foreign materials such as:
• particulates
• fibers
• residues
• Bulk material identification
• Identification of constituents in multi-layered materials
• Quantification of silicone, esters, etc. as contamination on various materials

Model: Nicolet Protege 460

Sample Size - Varied, as small as 10 µm.

Vacuum compatibility not an issue, samples may be liquid, solid, or gaseous form.

Thin organic films on a reflective surface (e.g. gold) can be analyzed in situ using the reflectance mode of the microscope.

The outer 1-10 µm of a material can be analyzed using attenuated total reflectance (ATR).

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