Determination of unsaturated fatty acids with a migrating double bond in complex biological matrices by gas chromatography with flame ionization and mass spectrometry detection

Abstract

We present the results of determination of unsaturated fatty acids (FAs) in foods of animal origin. It is shown that, in addition to the main component, monounsaturated cis-9-octadecenoic (oleic) acid, other fatty acids may be present in the composition of lipids, depending on the type of raw materials used to prepare the food product. The determination of these acids can significantly vary depending on the presence of impurities and assay conditions. It is demonstrated that gas chromatographic systems with a flame ionization detector, conventionally used for the determination of the fatty acid composition, are useless for the reliable identification of close structural analogues of unsaturated essential fatty acids. The conditions of determination of these compounds with mass spectrometric detection are selected. The effect of the composition of analytes, which were animal ingredients, on the results is discussed. It is shown that the greatest difficulty is the determination of unsaturated fatty acids present in test samples of different aetiologies in amounts not exceeding 0.05–0.1%.