Development of a headspace solid-phase microextraction gas chromatography–mass spectrometric method for the determination of short-chain fatty acids from intestinal fermentation

The determination of short-chain fatty acids produced by colonic fermentation can provide useful information as a tool to evaluate prebiotic effects of foods with beneficial effects on human health. In this study, we developed and validated a headspace solid-phase microextraction gas chromatographic–mass spectrometric method for the determination of underivatised short-chain fatty acids produced in an in vitro fermentation model. A divinylbenzene/Carboxen/polydimethylsiloxane fibre was used. Solid-phase microextraction conditions, i.e., extraction temperature, extraction time and salt addition were optimised by means of a central composite face-centred experimental design. The method was validated in terms of limit of quantification, accuracy, precision and linearity. The developed method was then applied to the analysis of short-chain fatty acids produced by the fermentation of faecal cultures derived from bread enriched with different kinds of dietary fibres.