HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS OF POLYPHENOLIC COMPOUNDS PREDOMINATING IN SHERRY MUSTS

A chromatographic procedure has been developed for the analysis of polyphenolic compounds in sherry musts. The procedure allows for the use of internal standards to control the different steps of the analysis. A C-18 reversed-phase column of 25 cm length and 4 mm diameter charged with 5 mu m particle size filling is used in connection with a gradient in stages consisting of a 2% acetic acid solution in methanol. The choice of the gradient has been previously worked out as applied to a mixture of 22 polyphenolic compounds. In order to ensure the stability of the must samples they are mixed with 10% dimethylformamide and 2% ascorbic acid. The internal standard is then added to the samples, which are subsequently submitted to a continuous rotary extraction process for 3 h using diethyl ether.