Highly sensitive electrochemical detection of dopamine using a poly(8-amino-naphthalene-2-sulfonic acid)-modified glassy carbon electrode

This work describes the fabrication of a poly(8-amino-naphthalene-2-sulfonic acid)-modified glassy carbon electrode (poly(ANSA)/GCE)-based electrochemical sensor for the detection of dopamine (DA). The electrode was developed by electropolymerizing 8-aminonaphthalene-2-sulfonic acid in an acidic solution, and it was examined using linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electroactive surface area of poly(ANSA)/GCE was 0.11 cm 2 was significantly larger than that of the bare GCE (0.07 cm 2 ), which improved the oxidation current of DA. Our experimental results showed the involvement of 2 electrons and 2 protons in the electrochemical redox reaction of DA. Moreover, the rate constant and diffusion coefficient of DA at poly(ANSA)/GCE were found to be 4.4 × 10 ³ M⁻¹s⁻¹ and 8.7 × 10⁻⁶ cm²s⁻¹ , respectively. The sensor showed a low detection limit of 0.089 µM and a broad linear detection range of 0.5 – 100 µM. Studies on selectivity verified that common analytes had little effect. DA detection in pharmaceutical formulations was accomplished with success using this approach, yielding recoveries ranging from 94.1 % to 102.4 %. According to the findings, poly(ANSA)/GCE shows promise as a viable option for real-world DA sensing applications.