Capillary electrophoresis of o-phenylenediamine derivatives (quinoxalines) of dicarbonyl sugars

Dicarbonyl sugars were separated by capillary electrophoresis as o-phenylenediamine derivatives (quinoxalines). Tetrabutylammonium bromide was used as a modifier; n-arabino-2-hexosulose (n-glucosone), D-lyxo-2-hexostdose (D-gdaCtOSOnC), 7-deoxy-L-galacto-2-hexosulose and 5-hydroxy-2,3dioxohexanal served as standards. The separation procedure was optimized with respect to pH, buffer and solute concentrations. In most instances optimum separations were obtained in 75 mM borate buffer (pH 11.0); 0.04 mg/ml was found to be the optimum sample concentration. The detection limit was ca. 0.1 pmol. Analyses of a mixture of fermentation products or Maillard reaction products show the applicability of the method.