STERYL ESTER ANALYSIS AS AN AID TO THE IDENTIFICATION OF OILS IN BLENDS

Sixty steryl esters have been synthesised in simple mixtures and used to optimise conditions for the separation of steryl esters by high performance liquid chromatography (HPLC) and gas chromatography (GC). Both techniques give good separations of many steryl esters, but the techniques complement each other since the elution sequence differs. A steryl ester-rich fraction has been isolated from 14 oil samples by thin-layer chromatography and analysed by GC and HPLC. GC analysis is more sensitive and faster than HPLC, and also has the advantage that residual triacylglycerols are separated from the steryl esters. The pattern of chromatographic peaks is similar for different samples of the same oil, but varies widely for different oils. It is therefore concluded that GC analysis of the intact steryl ester fraction may be useful as a technique for identifying mixtures of oils.