Determination of aliphatic alcohols, squalene, alpha-tocopherol and sterols in olive oils: direct method involving gas chromatography of the unsaponifiable fraction following silylation

In general, analyses for aliphatic alcohols, sterols and tocopherols in veg etable oils are performed separately. A simple and reliable procedure is pr esented for the quantification of the alkanols, squalene, alpha -tocopherol and sterols in olive oils by a direct method involving gas chromatographic (GC) analysis of the unsaponifiable fraction after silylation. The method eliminates the need for a preliminary thin-layer chromatographic (TLC) frac tionation prior to GC. External standard calibration with reference substan ces was used for the quantification of squalene, alpha -tocopherol and ster ols and internal standard calibration for the quantification of aliphatic a lcohols. The analyte recovery and the repeatability of the quantitative res ults were evaluated and were acceptable for routine use.