Determination of hydrochlorothiazide and rutin in Chinese herb medicines and human urine by capillary zone electrophoresis with amperometric detection

In this paper, capillary zone electrophoresis with amperometric detection (CZE-AD) was firstly applied to the simultaneous determination of rutin (RT) and hydrochlorothiazide (HCT) in compound Chinese herb medicines and human urine samples. The two analytes could be perfectly analyzed within 12 min and showed significant current responses at carbon electrode under the optimum conditions. It was found that the linear range of HCT was from 2.0×10^-6 to 1.0×10^-4 mol l^-1 and that of RT was from 1.0×10^-6 to 1.0×10^-4 mol l^-1. Their sensitivity was determined by linear regression and calculated as 7.02×10⁴ and 2.17×10⁵ nA l mol^-1, respectively, and their detection limits were 5.0×10^-7 and 2.0×10^-7 mol l^-1, respectively (S/N=3). Above results demonstrated that this method was of high sensitivity, good repeatability, high selectivity and could be used in metabolic kinetics studies of medicines. Satisfactory results were obtained when this method was used to simultaneously analyze the amounts of RT and HCT in one general compound Chinese herb medicine - Zhen Ju jiang Ya Pian and human urine samples.