DETERMINATION OF STEROLS AND TRITERPENIC DIALCOHOLS IN OLIVE OILS USING HPLC SEPARATION AND GC ANALYSIS - STANDARDIZATION OF THE ANALYTICALMETHOD

A method is developed for the analysis of sterols together with triter penic alcohols (erythrodiol and uvaol) in vegetable oils. The method i nvolves obtention of the unsaponifiable matter, isocratic HPLC separat ion 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 separa tions are compared. A collaborative trial comparing HPLC-sterols+dialc ohols and CCF-sterols (official) methods is carried out. For Delta 7-s terols, higher values and better repeatability and reproducibility wer e observed in the first method, but no differences for the remainder s terols were found. The erythrodiol+uvaol determinations by HPLC-sterol s+dialcohols and CCF-sterols+dialcohoIs (official) methods resulted in similar precision.