An electrochemical sensor based on poly (solochrome dark blue) film coated electrode for the determination of dopamine and simultaneous separation in the presence of uric acid and ascorbic acid: A voltammetric method

In this paper, the carbon paste electrode (CPE) was modified with poly- Solochrome dark blue (poly-SDB), through polymerization process, and it was used for the sensitive and selective determination of dopamine (DA). The simultaneous determination of Dopamine (DA) Ascorbic acid (AA) and Uric acid (UA) in 0.1 M Phosphate buffer solution (PBS) of pH 6.0 was carried out by employing differential pulse voltammetric technique (DPV). The effect of pH, concentration, scan rate, accumulation time, repetability and reproducibility of DA was studied at poly-SDB film modified electrode. The poly-SDBCPE exhibited a strong electrocatalytic action toward the oxidation of DA, AA and UA. The overlapping voltammetric response of biomolecules separated in to three well defined peaks with lower oxidation potential and significant increase in the anodic peak currents in the presence of poly-SDBCPE was achieved. The results showed a good sensitivity, selectivity and high reproducibility of electro synthesized polymer electrode. The limit of detection, limit of quantification and correlation coefficient of DA at poly-SDBCPE was 0.8 μM, 2.8 μM and 0.99765 respectively. The effect of interference was studied by DPV technique. The developed modified electrode was used for the analysis of DA in pharmaceutical formulations with satisfactory results. The interfacial electron transfer behavior of DA was studied by electrochemical impedance spectroscopy (EIS) and results showed that the charge transfer rate was enhanced at poly- SDBCPE, when compared with bare CPE, glassy carbon electrode (GCE) and platinum electrode (Pt).