The content and composition of sterols and sterol esters in sunflower and poppy seed oils

Analysis of steroidal lipids by gas and liquid chromatography

This article describes the most commonly used procedures and recent laboratory methodologies using gas and liquid chromatography developed for separation and quantitation of non-saponifiable steroidal lipids from clinical (human) studies, edible fats and oils or fatty foods.

Analysis of steryl esters in cocoa butter by on-line liquid chromatography-gas chromatography

On-line liquid chromatography-gas chromatography (LC-GC) has been applied to the analysis of steryl esters in cocoa butter. Separation of the steryl esters was achieved after on-line transfer to capillary GC. HPLC removes the large amount of triglycerides and pre-separates the components of interest, thus avoiding time-consuming sample preparation prior to GC analysis. The identities of the compounds were confirmed by GC-MS investigation of the collected HPLC fraction and by comparison of the mass spectra (chemical ionization using ammonia as ionization gas) to those of synthesized reference compounds. Using cholesteryl laurate as internal standard, steryl esters were quantified in commercial cocoa butter samples, the detection limit being 3 mg/kg and the quantification limit 10 mg/kg, respectively. Only slight differences in percentage distributions of steryl esters depending on the geographical origin of the material were observed. The patterns were shown to remain unchanged after deodorization. The method described might be a valuable tool for authenticity assessment of cocoa butter.

Determination of sterol and triterpene alcohol acetates in natural products by reversed-phase liquid chromatography and gas chromatography-mass spectrometry

A partial separation of nine sterol acetates and seven triterpene alcohol acetates by reversed-phase liquid chromatography is described. Good results are obtained using acetonitrile-water (90:10, v/v) as mobile phase with an UV detector at 205 nm. The variation in sterol sensitivity shows that this technique is not suitable for quantitative analyses. A combination of this technique for the fractionation of the natural sterol mixture, gas-liquid chromatography for quantitation and gas chromatography-mass spectrometry for identification is necessary for the determination of sterol compounds contained in natural products. An example of the separation, identification and quantitation of sterol acetates from sunflower seed oil is given.