Novel photoelectrochemical sensing of Levodopa drug with W-doped BiVO4 photoelectrode: Performance improvement by engineering surface and physical properties

Document Type : Original Article

Authors

1 Department of Chemistry, Faculty of Basic Sciences, Hakim Sabzevari University, Sabzevar, Iran

2 Advanced Photoelectromaterials Research Core, Faculty of Basic Sciences, Hakim Sabzevari University, Sabzevar, Iran

3 Department of Physics, Faculty of Basic Sciences, Hakim Sabzevari University, Sabzevar, Iran

Abstract

The detection and quantification of levodopa a critically important drug in the treatment of Parkinson’s disease is of significant clinical and analytical interest. In this study, a photoelectrochemical sensor based on tungsten-doped BiVO4 photoelectrodes is introduced for the sensitive determination of levodopa. For the first time, this work demonstrates that the choice of tungsten precursor plays a pivotal role in enhancing the performance of W-doped BiVO4 photoelectrodes and enables accurate levodopa detection in biological and pharmaceutical samples. Two distinct tungsten precursors pure tungsten powder and sodium tungstate salt were employed to synthesize two differently doped BiVO4 photoelectrodes. The influence of the tungsten precursor type on the surface characteristics and sensing performance of the photoelectrodes was systematically evaluated using electrochemical impedance spectroscopy (EIS) and chronoamperometry under simulated solar irradiation. Surface morphology, roughness, wettability, and optical properties were characterized via scanning electron microscopy (SEM), confocal laser scanning microscopy (for surface roughness analysis), water contact angle measurements, and UV-Vis spectroscopy. Results revealed that the photoelectrode synthesized using pure tungsten powder exhibited higher porosity, increased surface roughness, enhanced hydrophilicity, and superior light absorption collectively contributing to a larger electroactive surface area and improved photoelectrochemical activity. Furthermore, this electrode demonstrated higher sensitivity, a lower limit of detection, and a broader linear concentration range for levodopa. These findings highlight an innovative strategy for the rational design of high-performance, practical photoelectrodes tailored for the detection of biologically and pharmaceutically relevant analytes.

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Applied Chemistry Today
Volume 20, Issue 76
December 2025
Pages 195-208

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