Compositional analysis of polyunsaturated fatty acid oil by one-step thermally assisted hydrolysis and methylation in the presence of trimethylsulfonium hydroxide

Thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of trimethylsulfonium hydroxide (TMSH) was applied to the determination of fatty acid composition of lipids containing polyunsaturated fatty acid residues. By using this method, the polyunsaturated fatty acid (PUFA) components as well as saturated and monounsaturated fatty acid residues were observed almost quantitatively as their methyl eaters on the resulting chromatogram without causing any appreciable isomerization and/or degradation. On the basis of these peak intensities, the fatty acid compositions in soybean oil and sardine oil samples were rapidly and precisely estimated with less than 6% of the relative standard deviations even for PUFA components such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). (C) 1999 Elsevier Science B.V. All rights reserved.