Simply, it is the absorption measurement of different IR frequencies by a sample positioned in the path f an IR beam. The main goal of IR spectroscopic analysis is to determine the chemical functional groups in the sample. Different functional groups absorb characteristic frequencies of IR radiation. Using various sampling accessories, IR spectrometers can accept a wide range of sample types such as gases, liquids, and solids. Thus, IR spectroscopy is an important and popular tool for: * Identification of unknown materials. Determination of the quality or consistency of a sample. * Determination of the amount of components in a * Identification of all types of organic and many types of inorganic suture. Compounds. * Determination of functional groups in organic materials. * Determination of the molecular composition of surfaces. * Identification of chromatographic effluents. * Quantitative determination of compounds in mixtures. * Non-destructive method. * Determination of molecular conformation (structural isomers) and psychotherapist (geometrical isomers). Determination of molecular orientation (polymers and solutions). By interpreting the infrared absorption spectrum, the chemical bonds in a molecule can be determined. FITS spectra of pure compounds are generally so unique that they re like a molecular “fingerprint”. While organic compounds have very rich, detailed spectra, inorganic compounds are usually much simpler. For most common materials, the spectrum of an unknown can be identified by comparison to a library of known compounds.
Finger print region every compound a very complicated series of absorptions occur between wave numbers 500 to 1500 due to a variety of bending and stretching within the molecule. This region is called the finger print region. Each compound has a unique set of troughs within the fingerprint region that can be used to identify the molecule. It is hard to identify individual troughs due to specific bonds in the fingerprint region. Attenuated Total Reflectance (TART)Len Attenuated Total Reflectance (AT R) spectroscopy all that is required for analysis is that the sample of interest be brought into contact with the TART crystal.
The infrared beam is passed into the TART element such that its angle of incidence exceeds the “critical” angle. Under this condition total internal reflection of the beam occurs and a standing evanescent wave is established at the TART crystal/sample interface. The amplitude of this wave decays rapidly with increasing distance from the reflecting interface thus sample concentration and thickness are not a concern for these measurements.
Minimal to no sample preparation is required for this technique and a wide variety of solids and some liquids (dependent upon crystal material) can be analyzed using TART[Ref 3]Zinc Slender (Sense) Compensation Slender (Sense) is the most popular material for infrared application and it is chemically inert. Due to very wide transmission range covering 0. 6 to 20 m m C.V. grown Sense high optical quality material is seed to manufacture optical components (windows, mirrors, lenses etc. ) for high power IR lasers. [Reef] I Materials and Methods.