Gas chromatographic resolution on polar open-tubular columns of saturated and unsaturated wax ester isomers differing in combinations of acyl and alcoholic groups

Abstract

The gas chromatographic resolution of saturated and unsaturated wax ester isomers having the same carbon number and the same degree of unsaturation, prepared from various fatty acids and fatty alcohols, was carried out on open-tubular glass capillary columns coated with a cyanosiloxane, SP-2340. Satisfactory resolution was achieved at lower column temperatures (up to 240°C) by introducing very small amounts of samples (several nanograms per component) into a short column (15 m), with hydrogen as the carrier gas. Equivalent chain lengths (ECLs) of wax ester isomers with 32-42 carbon atoms and with 1-6 double bonds are presented. The ECLs of polyunsaturated wax esters were significantly dependent on column temperature. The influence of column temperature on resolution is discussed.