Copper-decorated poly(3-amino-5-mercapto-1,2,4-triazole)-modified glassy carbon electrode-based electrochemical sensor for the simultaneous determination of L-Dopa and Vanillylmandelic acid-an expeditious tool for monitoring neuroblastoma and hepatocellular carcinoma

Catecholamine precursors and metabolites are emerging as a prominent biomarker for the prognosis and diagnosis of many pathological conditions. This article details the fabrication, features and efficacy of the voltammetric sensor based on copper nanoparticles (CuNP)-decorated poly-3-Amino-5-mercapto-1,2,4-triazole-modified glassy carbon electrode p(Cu-AMT/GCE) for the individual and simultaneous determination of L-Dopa and Vanillylmandelic acid (VMA). The modified electrode has been characterised via different analytical techniques. The CuNP-decorated polymeric film enabled the formation of well-defined and well-separated oxidation peaks for the analytes with a limit of detection 6.80 x 10-8 mol L-1 and 9.90 x 10-8 mol L-1, respectively, for L-Dopa and VMA. Scan rate studies reveal the involvement of a reversible two electron-two proton reaction for the electrooxidation of L-Dopa and an irreversible, one electron-one proton reaction for VMA on p(Cu-AMT/GCE). The credibility of the sensor was ascertained from reproducibility, repeatability and stability studies. The satisfactory results obtained from the interference studies and adequate recovery values achieved from spike recovery analysis in synthetic physiological fluids substantiate the practical applicability of the sensor.