Rapid and simultaneous analysis of free sterols, tocopherols, and squalene in edible oils by coupled reversed-phase liquid chromatography gas chromatography

On-line coupling of reversed-phase liquid chromatography and gas capillary chromatography (RPLC-GC) using a programmed temperature vaporizer (PTV) as interface is used for the direct and simultaneous analysis of free sterols, tocopherols, and squalene of edible oils by direct injection (that is, without the need for prior enrichment of the sample). The proposed method allows large volume fractions of water methanol eluents to be transferred into the GC system, 2000 mu L/min being the speed of sample introduction. The overall procedure including LC preseparation, transfer from LC to GC, and GC analysis takes <1 h.