Chapter 4 Fourier transform infrared spectroscopy: Principles and applications

This chapter focuses on the application of Fourier transform infrared (FTIR) spectroscopy in the quantitative analysis of foods. It discusses the fundamental principles of IR spectroscopy, and describes the instrumentation, data handling techniques, and quantitative analysis methods employed in FTIR spectroscopy. Mid-infrared (IR) sampling techniques are most useful in FTIR analysis of foods. Molecular absorption of electromagnetic radiation in the IR region of the spectrum promotes transitions between the rotational and vibrational energy levels of the ground electronic energy state. An infrared spectrometer essentially consists of a source of continuous IR radiation, a means for resolving the IR radiation into its component wavelengths, and a detector. Radiation from the IR source is divided into a sample beam and a reference beam and passes through the sample and a reference, placed in the respective beams.