LIQUID CHROMATOGRAPHY WITH MULTI-CHANNEL ELECTROCHEMICAL DETECTION FOR THE DETERMINATION OF RESVERATROL IN WINE, GRAPE JUICE, AND GRAPE SEED CAPSULES WITH AUTOMATED SOLID PHASE EXTRACTION

Abstract

A sensitive and selective liquid chromatography/ electrochemistry method with multi-channel detection was developed for the determination of the natural product trans-resveratrol in wines, grape juice, and grape seed capsules. Samples were prepared with an automated solid phase extraction workstation. Chromatographic separation was achieved on a C18(100 × 2.0 mm) 3 μm column with a mobile phase containing 20 mM NaAc, 0.5 mM EDTA, pH 4.5, and 18 % acetonitrile at a flow rate of 0.4 mL/min. A four channel detector with glassy carbon electrodes was used, which can control up to four working electrodes simultaneously with applied potentials of +800, 700, 600, 500 mV vs. Ag/AgCl, and gave a better characterization of resveratrol in the complex matrices. The calibration curve was linear over the analytical range of 5–1000 ng/mL. With this method the content of resveratrol in different wines, grape juice and grape seed capsules was determined.