NEAR INFRA RED ANALYSIS

Abstract

The existence of infrared energy was discovered by Herschel in 1800 but it was sometime before it was realised that there was a continuous spectrum of electromagnetic energy as shown in the diagram, figure 1. This diagram also shows the division of infrared energy into near, fundamental and far regions. The absorption of energy in the fundamental region is caused by energy changes within the molecules of the sample being irradiated. These are typically bending, rocking, and wagging vibrations of an atom relative to other atoms in the molecule. The fundamental region has been investigated and applied to analysis for the last eighty years and many analytical laboratories have, or have access to, an infrared spectrometer working in this region. It is particularly useful for identification of organic compounds because of the characteristic spectra which are produced. Absorptions in the near infrared are caused by multiples or combinations of fundamental absorbencies. These produce spectra showing broad over‐lapping peaks which are of little use for characterisation.

Citation

Davies, A.M.C. (1982), "NEAR INFRA RED ANALYSIS", Nutrition & Food Science, Vol. 82 No. 5, pp. 5-6. https://doi.org/10.1108/eb058909