Chromatographic analysis of polyglycerols and their fatty acid esters

Polyglycerols and their fatty acid esters have been analyzed by gas-liquid chromatography (GLC) as trimethylsilyl ether derivatives. Linear diglycerols and triglycerols were isolated from commercial polyglycerols by vacuum distillation. Mono- and di-fatty acid esters were synthesized in the laboratory. Two isomers of diglycerol have been separated and identified. GLC analysis was carried out on columns packed with 3% JXR on Gas Chrom Q. Response factors for diglycerol and triglycerol relative to glycerol have been established. Commercial polyglycerol esters are shown to be mixtures of glycerol, free fatty acids, mono- and diglycerides, and mono- fatty acid esters of diglycerol and triglycerol. Separation of free polyglycerols and their esters is also demonstrated by thin-layer chromatography on Silica Gel-G containing 4.0% boric acid.