Glass Capillary Gas Chromatography of Fatty Acids from Refined Vegetable Oils

Abstract

High resolution gas chromatography of fatty acid methyl esters prepared from ten samples of refined vegetable oils was carried out on glass capillary columns. Effective separations of the positional isomers of monounsaturated fatty acids, the trans-9, cis-12 isomer of linoleate, and the cis-9, cis-12, trans-15 and trans-9, cis-12, cis-15 isomers of linolenate were performed on a Silar-5 CP or SP 2300 column. Additionally, the cis-9, trans-12, isomer of linoleate was separated on a Silar-10c or SP 2340 column. The cis-9, trans-12, cis-15 isomer of linolenate has not been detected in this study. Conversion of linolenate to the trans isomers during the refining process was 1329%, and that of linoleate was about 10% of the conversion of linolenate to the trans isomer. The fatty acid composition of refined vegetable oils is presented in detail.