A novel method was developed for separation and determination of D-gluconic acid produced during fermentation by capillary zone electrophoresis (CZE) with direct UV detection at 214 nm, using selected carrier electrolyte composed of 6 mM potassium biphthalate, 50 mM disodium hydrogen phosphate and 15% (v/v) acetonitrile. The effects of concentration of phthalate, phosphate and organic modifier (acetonitrile), as well as temperature for the separation were investigated. The method is simple, inexpensive and will make it very useful in the gluconic acid industry.