LAUSR

This investigation describes an integrated workflow for the parallel extraction and recovery of polyphenols and phytosterols from Pinot noir grape seeds. Using (E)-resveratrol and stigmasterol as exemplars, the approach employs two different molecular imprinted polymers in tandem for the extraction of these compounds and their subsequent analysis by capillary high-performance liquid chromatography (capHPLC) interfaced with electrospray ionisation tandem mass spectrometry (ESI MS/MS). Information on the selectivity of the solid-phase extraction processes was obtained through analysis of the binding behaviour of (E)-resveratrol- and stigmasterol-imprinted polymers using structurally similar polyphenols or phytosterols with the extent of binding determined from the capHPLC-ion trap ESI MS/MS data. This study documents with Pinot noir grape seed extracts and optimised solid-phase extraction protocols that the (E)-resveratrol-templated MIP enabled a very high recovery (99%) of the health-beneficial polyphenol (E)-resveratrol with co-purification of procyanidin and catechin/epicatechin. Further, the stigmasteryl-3-O-methacrylate-templated polymer resulted in high recovery (96%) of the phytosterol stigmasterol with co-purification of campesteryl glycoside. The results also demonstrate that rapid and high-resolution capHPLC-ESI MS/MS methods can be used as part of the work flow for selectivity optimisation and monitoring of the performance of MIPs intended for use in the solid-phase extraction of bioactive molecules with nutraceutical properties from agricultural waste streams.