The separation and determination of captopril in human serum and urine samples by means of high performance liquid chromatography(HPLC) with on-line electrogenerated Mn(Ⅲ) chemiluminescence detection was carried out. The method was based on the direct chemiluminescence reaction between captopril and Mn(Ⅲ), which was on-line electrogenerated by constant current electrolysis. The chromatographic separation was performed on a nucleosil RP-C18(250 mm×4.6mm i.d., 5 μm) column with an isocratic mobile phase consisting of acetonitrile-1% aqueous acetic acid(volume ratio 6∶4) at a flow-rate of 1.2 mL/min. The temperature was 25 ℃. The effects of several parameters on the HPLC resolution and CL emission were studied systematically. Under the optimal conditions, the linear range and detection limit for captopril are 5—800 ng/mL and 0.9 ng/mL, respectively. The relative standard derivation for 10.0 ng/mL captopril is 2.2%(n=11). The average recoveries for captopril in human serum and urine samples ranged from 94.8% to 103.2%, and the relative standard deviations of the quantitative results are below 3.4%. The proposed method had been applied to the determination of captopril in human serum and urine samples.
