Determination of sterols and triterpenic dialcohols in olive oils using HPLC separation and GC analysis. Standardization of the analytical method.

A method is developed for the analysis of sterols together with triterpenic alcohols (erythrodiol and uvaol) in vegetable oils. The method involves obtention of the unsaponifiable matter, isocratic HPLC separation with refractive index detector, preparation of silyl-derivatives, and analysis by capillary GC. Four procedures involving GC analysis of sterol and sterol+dialcohol fractions obtained by HPLC and CCF separations are compared. A collaborative trial comparing HPLC-sterols+dialcohols and CCF-sterols (official) methods is carried out. For Delta 7-sterols, higher values and better repeatability and reproducibility were observed in the first method, but no differences for the remainder sterols were found. The erythrodiol+uvaol determinations by HPLC-sterols+dialcohols and CCF-sterols+dialcohoIs (official) methods resulted in similar precision.