APPLICATION OF GAS–LIQUID AND THIN–LAYER CHROMATOGRAPHY IN FAT CHEMISTRY

Summary

Loss of polyunsaturated fatty acid methyl esters during gas–liquid Chromatographie analysis can be caused by metal injection systems and certain types of support. This is illustrated with a mixture of methyl eicosapentaenoate and methyl docosahexaenoate. The advantages of the use of on–column injection systems over metal injection systems is further demonstrated by the analysis of 2–hydroxy sterculic acid methyl ester.

The influence of support treatment, such as acid washing or silanizing is demonstrated in the separation of saturated and unsaturated fatty acid methyl esters and steroids.

It is explained why such compounds as hydroxy fatty acid methyl esters cannot be analysed on polyester immobile phases without any loss occurring. Neither are these polyester phases suitable for the analysis of cyclopropenoid acids. The application of GLC in the analysis of triglycérides and a sterol mixture is described in addition to its use in the identification of cholesterol in some vegetable oils and that of 2–hydroxysterculic acid in the seeds of the Bombacopsis and Pachira genus.