Determination of trans-resveratrol and other polyphenols in wines by a continuous flow sample clean-up system followed by capillary electrophoresis separation

A new method coupling flow injection (FI) with capillary electrophoresis (CE) has been developed using diode array detection to measure the concentration of trans-resveratrol in wines, in particular because of the interest in its biological properties and cancer prevention. A FI system furnished with a C-18 minicolumn was used to clean up the wines by solid phase extraction prior to CE. The analytes were eluted from C-18 by using methanol and then driven from the FI system to the autosampler of the CE equipment by a programmable arm. The 3σ detection limit ranged from 0.05 mg l−l (trans-resveratrol) to 0.36 mg l−l [(−)epicatechin]. The recoveries of added trans-resveratrol and other polyphenols from synthetic wines were between 92% to 110%, (mean of 99%). The method is faster and simpler than those previously reported which used liquid–liquid extraction and liquid chromatography.