Gas-liquid chromatographic analysis of long chain isomeric glyceryl monoethers

Abstract

A quantitative method is described for the gas chromatographic analysis of glyceryl ethers using their trifluoroacetate (TFA) and trimethylsilyl (TMS) ether derivatives. Both derivatives are prepared at room temperature by reactions that proceed virtually to completion in less than 15 min, eliminating time-consuming derivative preparations and laborious clean-up steps of unreacted materials required by other methods. Gas-liquid chromatography (GLC) resolves the 1- and 2-isomers of the glyceryl ether TFA derivatives, which have not been separated previously. Purified synthetic 1- and 2-glyceryl ethers, including saturated and mono- and diunsaturated, were used to evaluate several polar and nonpolar liquid phases for the analysis of the TFA and TMS derivatives. Analyses can be made on some liquid phases normally used for methyl esters, while others are unsatisfactory. A mixture of isomeric C₁₈ saturated and monoand di-unsaturated TFA derivatives was partially resolved; however, a complete analysis of this mixture can be made by preliminary separation of the unsaturates on silver-ion-impregnated thin-layer plates or by GLC analysis alone with three different phases.