Determination of tocopherols and sterols in vegetable oils by solid-phase extraction and subsequent capillary gas chromatographic analysis

In general, analyses of tocopherols and sterols are performed separately in vegetable oils. By applying solid-phase extraction (SPE) prior to capillar y gas chromatography, a simple and reliable procedure for the quantificatio n of both tocopherols and sterols in a single analytical run has been devel oped. SPE was used as sample clean up procedure for the separation of these minor components from the triacylglycerol matrix, replacing time consuming saponification or on-line LC-GC. The analysis of tocopherols and free ster ols in five different vegetable oils illustrates robustness and reliability of this method outlined. Quantification of the analytes was performed by e xternal calibration with reference substances and internal standardization. The recovery of the procedure as well as the repeatability of the quantita tive results have been evaluated. (C) 1999 Elsevier Science B.V. All rights reserved.