Electrochemical Simultaneous Determination of Levodopa and Benserazide in Aniline and Multi–Walled Carbon Nanotube Modified Sensor

The present study reports the development of a highly sensitive electrochemical sensor for the simultaneous determination of levodopa and benserazide, two pharmacologically active substances used in the treatment of Parkinson's disease. The sensor was fabricated by electropolymerization of aniline on a glassy carbon electrode (GCE) in a nonaqueous medium, followed by modification with multi-walled carbon nanotubes (MWCNTs). The synergistic effect of polyaniline and MWCNTs resulted in enhanced electrochemical performance, providing high selectivity and sensitivity toward the target analytes. The modified electrode exhibited well-defined differential pulse voltammetry (DPV) responses, allowing for quantitative determination of levodopa in the linear range of 500-1000 µM and benserazide in the range of 100-500 µM, with detection limits of 67.01 µM and 163.60 µM, respectively. The electrochemical behavior of the sensor was evaluated under various conditions, including film thickness, supporting electrolyte type, and pH variations, to optimize its performance. The sensor demonstrated excellent repeatability, stability, and resistance to interference from ascorbic acid, a common interfering species. Additionally, the method was successfully applied to the determination of levodopa and benserazide in real urine samples and pharmaceutical formulations, achieving satisfactory recovery rates. These findings highlight the potential of the developed sensor as a reliable and cost-effective tool for clinical and pharmaceutical applications.