Simultaneous determination of sugars and organic acids by co-electroosmotic capillary electrophoresis with amperometric detection at a disk-shaped copper electrode

A novel approach to the simultaneous determination of sugars and organic acids by co-electroosmotic capillary electrophoresis with amperometric detection at a disk-shaped electrode was developed. The addition of cetryltrimetylammonium bromide (CTAB) to the carrier electrolyte not only established the co-electroosmotic conditions but also increased the detection sensitivity of the analytes studied. In the optimum carrier electrolyte system composed of 0.05 M NaOH and 0.20 mM CTAB, the simultaneous determination of tartaric acid, ascorbic acid, fructose, glucose, and sucrose can be accomplished within 14 min with precisions (RSD) less than 5% for peak height and 1.5% for migration time at the concentration level of 5 x 10(-4) M. The present method was successfully applied to the analysis of grape samples with recoveries in the range 95.0-103.0%. (C) 1998 Elsevier Science B.V. All rights reserved.