Capillary gas-liquid chromatography of faecal free and esterified neutral sterols

A method is described for the analysis of faecal free and esterified neutral sterols by high-resolution capillary gas-liquid chromatography (GC). After homogenization and filtration of the sample, free and esterified sterols are separated by reversed-phase Lipidex-5000 chromatography. The esterified sterols are saponified and analysed by GC. The free sterols are further fractionated on a Lipidex-5000 straight-phase column into oxo- and hydroxysterols, respectively. The GC separation of the compounds is achieved with an SE-30 open-tubular silica capillary column. The mean recoveries of the authentic sterols are 90.0% ± 5.8% (SD) and the mean within-assay coefficients of variations are 3.7% ± 2.9% (SD). The method permits determination of (A) the main animal sterols (cholesterol, coprostanol, epicoprostanol, cholestanol, coprostanone and cholestanone), (B) the amount of total plant sterols (β-sitosterol, campesterol, stigmasterol and their metabolic conversion products) and (C) the degree of esterification ...