Determination of Free and Esterified Fatty Acids in Hydrocoles of Different Content of Polyunsaturated Fatty Acids by Gas–liquid Chromatography

This paper presents a new technique of hydrocole (bacteria, blue−green algae, phytoplankton, zooplankton, sponges, fish oil and seal fat) fatty acids (FA) methyl esters determination by gas-liquid chromatography. The polyunsaturated fatty acids (PUFA) contents in these objects were different. The distinguishing features of the technique are the next ones: efficiency, lipid extraction recovery ≥94% using the sonication during 10–15 min without sample drying, high PUFAs yield (≥97%) by reduction of oxidation up to 40% during methylation; exhaustive extraction of fatty acid methyl esters (FAMEs) including PUFA; a new approach to obtain of methyl esters of free fatty acids except using toxic reagents; accuracy of FAMEs quantification including ω-3-, ω-6-, ω-9-FA using the di-n-decyl ether as an internal standard and accuracy of measurements using “T14165QC Fish oil” standard sample (first). The technique is approbated for Baikal hydrocole FA determination from 20 to 2000 μg in the sample and might be used for scientific and applied tasks. The interlaboratory precision of FAME determination of phytoplankton and bacteria is ≤10%.