Simultaneous determination of benserazide and levodopa by capillary electrophoresis–chemiluminescence using an improved interface

A capillary electrophoresis coupling with indirect chemiluminescence detection method for the simultaneous determination of benserazide and levodopa has been developed. The detection interface was improved to simplify the capillary electrophoresis–chemiluminescence (CE–CL) system and the features of this improved interface were illustrated in this paper. The CE–CL conditions for the simultaneous determination of benserazide and levodopa were optimized. Under the optimal conditions, the CL intensity was linear with concentrations of levodopa in the range of 1.0 to 100.0 μg ml −1, and benserazide in the range of 10.0 to 1000 μg ml −1, respectively. The detection limits (S/N = 3) in turn were 1.85 μg ml −1 for BS and 0.12 μg ml −1 for L-dopa with relative standard deviations of less than 3%. The proposed method has been successfully applied to the determination of benserazide and levodopa in medopar tablets and spiked urine samples, demonstrating the feasibility and reliability of the proposed method.