GC/FT-IR ANALYSIS OF FATTY-ACID METHYL-ESTERS

An analytical method, based on coupled gas capillary chromatography and Fourier transform infrared spectrometry (GC/FT-IR), has been developed to determine the structure of fatty acid mixtures often found in the marine environment. In the case of saturated fatty acids, the method provides useful information concerning chain lengths and the presence of (1) branched methyl groups (iso or anteiso), (2) cyclopropanic structures, and (3) hydroxyl groups (two or three positions). Furthermore, the presence or absence of double bonds, as well as their stereochemistry and their number, in the case of cis polyunsaturated derivatives, can be determined. The method has required the development of a specific GC/FT-IR library of 46 fatty acid methyl esters generally found in the marine environment.