DETERMINATION OF TRANS-RESVERATROL AND OTHER POLYPHENOLS IN WINES BY A CONTINUOUS-FLOW SAMPLE CLEANUP SYSTEM FOLLOWED BY CAPILLARY ELECTROPHORESIS SEPARATION

A new method coupling flow injection (FI) with capillary electrophores is (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-ls by using methanol and then driven from the FI system to the autos ampler of the CE equipment by a programmable arm. The 3 sigma detectio n limit ranged from 0.05 mg l(-1) (trans-resveratrol) to 0.36 mg l(-1) [(-)epicatechin]. The recoveries of added trans-resveratrol and other polyphenols from synthetic wines were between 92% to 110%, (mean of 9 9%). The method is faster and simpler than those previously reported w hich used liquid-liquid extraction and liquid chromatography. (C) 1998 Elsevier Science B.V.