Infrared Spectra of Diacid and Triacid Triglycerides

Abstract

Seven diacid and five triacid saturated triglycerides have been investigated by infrared spectroscopy. The majority of absorption bands could be assigned with the help of the concept “diathesis.” A diathesis is a (part of a) molecule acting as a separate vibration unit. The spectra have practical value for identification purposes. It is demonstrated that from the spectra can be concluded: (1) the polymorphic form of the investigated sample (α, β‘, β); (2) the chain lengths of the three fatty acid moieties, i.e., the composition of the triglyceride; and (3) the position of these fatty acid moieties in the molecule, i.e., the isomer. Aided by tables with appropriate data, given here, unknown samples can be identified in most cases.