Migration order of wine anthocyanins in capillary zone electrophoresis

Capillary zone electrophoresis (CZE) is an advantageous alternative to liquid chromatography (LC) in the analysis of wine anthocyanins in terms of separation efficiency, analysis time and reagent consumption. Thirteen wine anthocyanins of a Tannat wine, including acylated and non-acylated anthocyanin monoglucosides, pyranoanthocyanins and flavanol derivates, were separated using a 46 cm × 75 (mu)m (i.d.) fused-silica capillary and a 50 mM sodium tetraborate buffer of pH 8.4 with 15% (v/v) methanol as modifier. Some of the pigments were isolated by LC fractionation and concentrated by lyophilisation. The reconstituted fractions were analysed by CZE in order to identify the compounds in the electrophoregram and to determine their migration times. The migration order found for the wine anthocyanins is discussed taking into account the molecular charge and mass, and the possibility of complex formation with tetraborate molecules.