Optimisation of sample preparation for the determination of trans-resveratrol and other polyphenolic compounds in wines by high performance liquid chromatography

Different methods for sample preparation as a preliminary stage for the simultaneous determination of trans-resveratrol and other polyphenolic compounds are compared with the aim to establish the best conditions for the determination of these compounds in wine samples by high performance liquid chromatography (HPLC). Sample preparation using liquid-liquid extraction and solid-phase extraction were compared. Liquid-liquid extraction using as organic solvent diethyl ether at pH 2.0 shows the best results. The dried extract was solved in methanol/water 1:1 (v/v) that improve drastically the separation efficiency. The developed method was applied to the analysis of wines from the Canary Islands.