Development of a sensitive flow-injection-chemiluminescence detection method for the determination of levodopa

A simple chemiluminometric method using flow injection has been developed for the determination of levodopa, based on its sensitizing effect on the weak chemiluminescence (CL) reaction between Na(2)SO(3) and acidic KMnO4. Under optimum experimental conditions, the CL intensity was linearly related to the concentration of levodopa from 3.4 x 10(-8) to 2.4 x 10(-5) mol/L and the detection limit was 1.1 x 10(-8) mol/L (s:n = 3). The relative standard deviation (RSD) of the proposed method calculated from 20 replicate injection of 3 x 10(-7) mol/L levodopa was 3.3%. The correlation coefficient was 0.997. The method was successfully applied to the determination of levodopa in commercial pharmaceutical formulations and spiked urine samples.