Infra Red Spectroscopy in Chemistry Essay Example | Topics and Well Written Essays - 750 words - 1

Infra Red Spectroscopy in Chemistry - Essay Example The absorbed radiation is converted into energy of molecular vibration by the sample molecules. The frequency of absorption of radiation depends on the masses of the atoms in the molecule, the force constants of the bonds, and the geometric structure of the molecule. Hence, the resulting spectrum is an exact replica of sample contents and its molecular structure as supported by Beer-Lambert Law (Duckworth, 1998) which states that there is a linear relationship between how much light is absorbed by a sample and the product of the concentration of the absorbing species and its path length. A close examination of infra-red spectrum fingerprints reveals that absorption peaks correspond to the frequency of vibration between the bonds of the atoms of sample material while the magnitude of peaks corresponds to the amount of material present. Since each sample has a unique molecular structure just like a fingerprint so no two unique molecular structures produce the same infra-red spectrum (l eaving few exceptions). Hence the information provided by infra-red spectra about the composition as well as the structure of a molecule of a sample material clearly paves a way for both qualitative a â€Å"positive identification† and (with an aid of modern software algorithms) quantitative i. e. â€Å"amount† (Introduction to Fourier Transform Infrared Spectrometry, 2001, p.3) analysis of material, an invaluable tool for QA/QC or contamination analysis applications. For example, Ethanol content is the single most important parameter in alcoholic beverage industries. ‘For many economic and regulatory reasons, convenient, accurate, and fast quantitative determination of ethanol in mixtures is important. With the increased importance of quality assurance in industries, Near-IR spectroscopy has become an important quantitative tool for solvent characterization’.