Improved resolution of natural diacylglycerols by gas-liquid chromatography on polar siloxanes

A new cyanoalkylphenylsiloxane (SILAR 5CP) liquid phase is shown to possess sufficient polarity to permit improved GC separations of natural diacylglycerols based on unsaturation and positional placement of fatty acids as well as on molecular weight, which was previously possible only on ethylene glycol succinate polyesters. Unlike the polyesters, the polar siloxane polymer has moderate thermal stability and provides GC columns which can be used for several months without replacing the packing. The GC analyses were made with conventional columns containing 3% SILAR 5CP on Gas Chrom Q at 270 degrees C isothermally. The diacylglycerols were chromatographed as the TMS ethers. Excellent seperations were obtained for the 1,2(2,3)- and 1,3-diacyglycerols derived from corn, linseed, peanut and cod liver oils and for the 1,2-diacyl-sn-glycerols from hepatic glycerophospholipids.