ABSTRACT
Infrared spectra contain detailed information on substances since all groupings of a molecule cause various characteristic vibrations. Furthermore, sometimes vibrations are shifted due to interactions of groupings with their environment. The absorption bands observed in the infrared spectral region (IR) are caused by molecular vibrations. Intramolecular vibrations, in which atoms of a molecule move relative to each other, are distinguished from intermolecular vibrations, in which molecules move relative to each other. Information on the conformations of macromolecules can be obtained by IR spectroscopy since vibrations within these molecules may couple with each other. Coupling of vibrations causes band splitting and/or shifting of bands in opposite directions due to Fermi resonance. A procedure to identify and determine quantitatively preservation compounds in food was described by Sudraud et al. Twenty grams of the test material is steam-distillated in the presence of phosphoric acid.
