DETERMINATION OF PROANTHOCYANIDINS AND CATECHINS IN BEER AND BARLEY BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH DUAL-ELECTRODE ELECTROCHEMICAL DETECTION

A method was developed to determine the flavanols prodelphinidin B3, p rocyanidin B3, (+)-catechin, and (-)-epicatechin by high-performance l iquid chromatography, using dual-channel electrochemical detection. Th is method was especially suited to the direct analysis of beer samples and to analysis of acetone extracts of barley samples, and was capabl e of determining proanthocyanidins and catechins at levels of 0.1-5.0 mg 1(-1). The use of dual-channel electrochemical detection also enabl ed unambiguous peak identification by measurement of collection effici encies. This method offered improved sensitivity and selectivity compa red with ultraviolet detection, and sample preparation procedures were greatly simplified. The method was applied to the comparison of stabi lized and unstabilized lagers, and to the analysis of different barley varieties grown in Ireland.