Gas chromatographic determination of fatty acids contained in different lipid classes after their separation by solid-phase extraction

A quick and successful procedure is presented for the separation of polar lipids, monoacylglycerols (MAGs), diacylglycerols and triacylglycerols (TAGs) and for fatty acid determination in the above-mentioned lipid fractions by gas chromatographic analysis, which was acceptable for physiological and nutrition studies. In the analysis of edible oils and biological tissue samples, lipid classes were separated and purified by solid-phase extraction (SPE) using an aminopropylsilica column. Fatty acids in the sn-2 position in edible oil TAGs were determined after previous 1,3-specific lipase hydrolysis and separation of 2-MAGs by SPE using an aminopropylsilica column. A preliminary study of the solid-phase extraction separation of lipid classes with stock standard solutions using styrene–divinylbenzene–methacrylate copolymer (Nexus), octadecylsilica (C18) and aminopropylsilica (NH2) was carried out and it was shown that NH2 was the best sorbent for the above-mentioned purpose.