Simultaneous determination of levodopa and benserazide using poly(3-methylthiophene) and a multi-walled carbon nanotube sensor.

Rapid, reliable, reproducible, and repeatable modified sensor designs have been developed to distinguish the binary mixture of levodopa and benserazide in the presence of ascorbic acid using voltammetric techniques. Sixteen designed sensors were prepared by dropwise of different concentrations and quantities of multi-walled carbon nanotube (MWCNT) dispersions to bare glassy carbon electrode (GCE) surface and also the bottom and the top of the poly(3-methylthiophene) films. The best simultaneous determination was accomplished with the sensor dropped 20 μL of 1.0% MWCNT to GCE. Under optimum conditions, the electrocatalytic oxidation peak currents of levodopa and benserazide showed linear dynamic range, good stability, and sensitivity with detection limit of 10.3 and 32.5 μmol L, respectively. The proposed method has been successfully applied for the determination of levodopa and benserazide in urine samples and pharmaceutical preparations, demonstrating the feasibility and reliability. [ABSTRACT FROM AUTHOR]