Studies on methanolysis of triglycerides on thin layer chromatoplate

Methanolysis of triglycerides on thin layer chro‐matography plate, for the preparation of correspond‐ing fatty acid methyl esters suitable for gas liquid chromatography analysis, has been studied with synthetic mixtures of pure tricaprylin, trilaurin, tri‐palmitin, and triolein. The long chain saturated glyc‐eride, tripalmitin, has been found to be least suscep‐tible to methanolysis. Plate temperature of 65 C and KOMe‐methanol reagent concentration of 1.0 N have been found to be optimal for samples containing large amount of trisaturated glyceride like tripalmitin without appreciable loss in short chain components by evaporation. For fats containing lower proportions of trisaturated glyceride like vegetable oils, a lower concentration, i.e., 0.5 N of the reagent can be used at the above temperature. Addition of lipid solvent like benzene in the reagent has little effect on the conversion. Long chain triglycerides containing one or more double bonds in the molecule respond more to this reaction than do trisaturated glycerides of the same carbon number. Fatty acid compositions of cottonseed and peanut oil triglycerides obtained by the GLC analysis of the methyl esters prepared by the present method and that of Luddy et al. [JAOCS 45:549 (1968)] have been found to agree well.