Selection of column and gradient for the separation of polyphenols in sherry wine by high-performance liquid chromatography incorporating internal standards

A chromatographic column was selected, out of five possibilities tested, which offered sufficient efficiency to separate 21 out of 22 polyphenolic compounds, and the optimum elution gradient. Applied to samples of ''fino'' sherry wine, a satisfactory resolution of peaks was achieved, which allowed for the inclusion of an internal standard. The chromatographic behaviour of three polyphenolic standard substances was studied using the column and gradient selected, with a view to using them as internal standards for controlling the reliability of the analysis. 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 detection at 340 nm; however, the possibility of using the other two phenolic acids, beta-resorcylic and 2,6-dimethyoxybenzoic acid, is not discarded as they could conveniently be made use of depending on the chromatographic profile of the sample to be analyzed.