SELECTION OF COLUMN AND GRADIENT FOR THE SEPARATION OF POLYPHENOLS INSHERRY WINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY INCORPORATING INTERNAL STANDARDS

A chromatographic column was selected, out of five possibilities teste d, which offered sufficient efficiency to separate 21 out of 22 polyph enolic compounds, and the optimum elution gradient. Applied to samples of ''fino'' sherry wine, a satisfactory resolution of peaks was achie ved, which allowed for the inclusion of an internal standard. The chro matographic behaviour of three polyphenolic standard substances was st udied using the column and gradient selected, with a view to using the m as internal standards for controlling the reliability of the analysi s. It was concluded that all three can be used for this task, although 2,5-dihydroxybenzaldehyde is the most suitable in terms of ease of de tection at 340 nm; however, the possibility of using the other two phe nolic acids, beta-resorcylic and 2,6-dimethyoxybenzoic acid, is not di scarded as they could conveniently be made use of depending on the chr omatographic profile of the sample to be analyzed.