Fourier Transform Infrared Spectroscopy Principles and Applications

Fourier Transform Infrared Spectroscopy Principles and Applications 

Ashraf A. Ismail, Frederick R. van de Voort, and Jacqueline Sedman 

Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, Ste-Anne de Bellevue, QC, Canada H9X 3V9. 

Mid-infrared (IR) spectroscopy is a well-established technique for the identification and structural analysis of chemical compounds. The peaks in the IR spectrum of a sample represent the excitation of vibrational modes of the molecules in the sample and thus are associated with the various chemical bonds and functional groups present in the molecules. Thus, the IR spectrum of a compound is one of its most characteristic physical properties and can be regarded as its fingerprint. Infrared spectroscopy is also a powerful tool for quantitative analysis as the amount of infrared energy absorbed by a compound is proportional to its concentration. However, until recently, IR spectroscopy has seen fairly limited application in both the qualitative and the quantitative analysis of food systems, largely owing to experimental limitations. 

The development of Fourier transform infrared (FTIR) spectroscopy during the past two decades has revitalised the field of IR spectroscopy. This is due not only to the superior performance of FTIR spectrometers by comparison to that of the dispersive IR spectrometers that they have virtually replaced, but also to a number of other factors. First, the development of FTIR 

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