Gas Chromatography of C18-Saturated and Unsaturated Fatty Acid Methyl Esters

Abstract

When diethylen glycol succinate polyester was used as stationary liquid phase of gas chromatography, the influences of various factors on the separation of methyl stearate and oleate peaks were investigated for both thermal conductivity detector and hydrogen flame ionization detector. Our experiments showed the following results. The degree of polymerization of polyesters slightly influenced upon the column efficiency in the range of molecular weight from 2, 700 to 5, 400. Rather, the influences of the procedur for supporting the polyesters on the solid supporters were considerable, and the species of supporters used had greatest influence upon the column efficiency. When the column became longer, the number of theoretical plates increased but the degree of resolution increased scarcely.Further, the relative responses in flame ionization detector were discussed for methyl esters of palmitic, stearic, oleic, linoleic and linolenic acids. The relative responses showed nearly close correlation between percentages of peak areas and weight percent when their contents were large. But when their contents were small, there was a tendency that percentages of peak areas of methyl stearate and oleate were higher than known weight percent, while percentages of peak areas of methyl linoleate and linolenate were lower than known weight percent.