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Phytosterol oxidation products (POPs) have been suggested to exert adverse biological effects similar to, although less severe than, their cholesterol counterparts. For that reason, their analysis in human plasma is highly relevant. Comprehensive two-dimensional gas chromatography (GC×GC) coupled with time-of-flight mass spectrometry (TOF-MS) has been proven to be an extremely powerful separation technique for the analysis of very low levels of target compounds in complex mixtures including human plasma. Thus, a GC×GC/TOF-MS method was developed and successfully validated for the simultaneous quantification of ten POPs in human plasma. The calibration curves for each compound showed correlation coefficients (R(2)) better than 0.99. The detection limits were below 0.1 ng mL(-1). The recovery data were between 71.0% and 98.6% (RSDs <10% for all compounds validated). Good results were obtained for within- and between-day repeatability, with most values being below 10%. In addition, non-targeted sterol metabolites were also identified with the method. The concentrations of POPs found in human plasma in the current study are between 0.3 and 4.5 ng mL(-1), i.e., 10-100 times lower than the typical values found for cholesterol oxidation products.

A majority of the 2.5 g PSTE and PSTA was hydrolysed during small bowel passage,which did not affect fat absorption as indicated by similar excretions of fatty acids in all periods. Consumption of increasing amounts of esterified phytosterols and phytostanols from enriched food formats should thereby have no adverse effects in this regard.

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Chromatography has a very long history in the analysis of edible oils and fats. Hyphenations of two chromatographic methods, or couplings of a chromatographic separation technique with spectroscopic detection and identification devices, are used if the resolving power of the technique needs to be improved. More recently, the analytical benefits of comprehensive two-dimensional (2D) chromatography, in its various operational modes, have been exploited by the oil and fat chromatographic community. In comprehensive 2D chromatography, the entire sample injected is subjected to two independent separation processes. In the present contribution, the principles of comprehensive 2D chromatography are briefly discussed. Next, the advantages of comprehensive separations for lipid analysis are illustrated using the concept of generic chromatographic applications. This concept distinguishes three generic reasons to apply chromatographic separations: target compound analysis, group-type separation, and chromatographic fingerprinting. Examples of how comprehensive multi-dimensional methods were successfully applied to solve problems in the edible oils and fats area are given. We believe that these multi-dimensional techniques truly add new dimensions to oil and fat analysis, providing researchers in the area with novel tools for unraveling edible oil or fat samples with their complex compositions.