Determination of sugars in Chinese traditional drugs by CE with amperometric detection

A simple, fast and reliable method, based on capillary zone electrophoresis with amperometric detection, for the separation and determination of sucrose, glucose, and fructose in Chinese traditional drugs, namely Astragalus Membranceus (Fish.) Bge, Angelica and Codonopsis pilosula (Franch.) Nannf. was described in this paper. A copper disk electrode was used as working electrode. The optimal conditions of separation and detection were 0.05 mol/l sodium hydroxide buffer (pH 12.7), 5 kV for the separation voltage and +0.65 V (vs. Ag/AgCl) for the detection potential. The linear ranges were from 5.0×10^-6 to 5.0×10^-4 mol/l for all three sugars. The all regression coefficients were more than 0.999. The detection limits were 1.0×10^-6 mol/l for glucose and fructose, and 4.0×10^-6 mol/l for sucrose. The method built in this paper was directly applied to the separation and determination of the three sugars in three Chinese traditional drugs without prior derivatization, and the content for every sugar in the drugs was first assayed. The assay results were satisfactory.