High-performance liquid chromatography of reaction mixtures from the oxidation and degradation of lactose

Abstract

A method is described for the high-performance liquid chromatographic analysis of reaction mixtures from the heterogeneously catalysed oxidation of lactose to lactobionate and the homogeneous alkaline oxidative degradation of lactose to b-0-o-galactopyranosyl-(l-3)-r)-arabinonate.Two columns in series, a resin-based anion-exchanger in the acetate form and a resin-based cation exchanger in the H+ form with water as the eluent, allow the quantification of the sugars without interference from the oxidation and degradation products. Occasionally an RP-18 reversed-phase column was used for the determination of lactulose in the reaction samples. A resin-based anion-exchange column in the Cl-or SO:-form allows the determination of the anionic oxidation and degradation products without interference from the sugars present in the reaction samples. In the analyses of the anionic oxidation and degradation products a method was developed to determine some of these. products without their pure standards. The method is based on the regular behaviour in refractive index detection of members of a homologous series of aldonates.