The Analysis of Pentoses in Dry Wine by High Performance Liquid Chromatography with Post-Column Derivatization

Abstract

A method was developed for measuring pentose concentrations in wine by high performance liquid chromatography (HPLC) with post-column derivatization using tetrazolium blue (TZB). Detection of the reduced TZB was at 520 nm. Many potential interferences were avoided because the method is specific for reducing compounds. Sample preparation is very short, and separation is achieved in about an hour on an Aminex HPX-87P monosaccharide analysis column, a cation exchange resin crosslinked with lead. The concentrations of the pentoses xylose, arabinose, and ribose and of the hexoses glucose, fructose, and rhamnose were determined. The method is only applicable to dry wines because relatively large glucose concentrations affected the quantification of xylose. The method had a detection limit of at least 0.3 µg for each sugar and at least to 0.15 µg for xylose. The linear range extended to 2.4 µg for each of the sugars except fructose, which was linear only to 1.2 µg. Two dry red wine samples were run, and the concentrations of the six sugars were determined. The xylose concentration was estimated in one sample because the concentration of glucose was about 19 times greater than the xylose concentration. The second wine sample appeared to have an interfering peak eluting with glucose and xylose. Therefore, their concentrations were also estimated.