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 organ ic acids by co-electroosmotic capillary electrophoresis with amperomet ric detection at a disk-shaped electrode was developed. The addition o f 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 carr ier electrolyte system composed of 0.05 M NaOH and 0.20 mM CTAB, the s imultaneous determination of tartaric acid, ascorbic acid, fructose, g lucose, 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 successful ly applied to the analysis of grape samples with recoveries in the ran ge 95.0-103.0%. (C) 1998 Elsevier Science B.V. All rights reserved.