Screen-printed electrodes decorated with low content Pt–Ni microstructures for sensitive detection of Zn(II), ascorbic acid and paracetamol in pharmaceutical products and human blood samples

Abstract

In this study, we report for the first time, a method for simultaneous detection of paracetamol (PA) and its toxic impurities, 4-aminophenol (4-AP), as well as commonly co-formulated drugs, ascorbic acid and zinc (AA and Zn(II)), using screen-printed electrodes (SPEs) as a sensing platform. To improve the electrochemical performance of the SPEs, these are decorated with platinum and nickel microstructures (Pt–Ni), using a simple electrodeposition technique. The structures and morphologies of the synthesized Pt–Ni/SPE electrode were confirmed by FE–SEM, TEM, EDX, XRD and AFM measurements. Furthermore, electrochemical characterization of the as-prepared sensor was investigated using cyclic voltammetry and electrochemical impedance spectroscopy methods. Under optimum conditions, the content of 4-AP, PA, AA and Zn(II) was quantified using cyclic voltammetry, differential pulse voltammetry and square-wave voltammetry techniques. The designed sensor exploits a dual effect, leveraging the efficiency of Pt for Zn(II) detection and Pt–Ni for the detection of 4-AP, AA, and PA. On one hand the as-prepared Pt–Ni/SPE sensor exhibits a linear response towards 4-AP and PA, ranging from 0.5 to 200 μM for both, with detection limits of 0.33 µM and 0.23 µM (S/N = 3) for 4-AP and PA, respectively. On the other hand, it demonstrates a linear response towards PA, AA, and Zn(II), ranging from 0.01 to 0.8 μM for Zn(II), 10 to 1800 μM for AA, and 0.5 to 200 μM for PA, with detection limits of 0.004 µM, 9.0 µM, and 0.15 µM for Zn(II), AA, and PA, respectively. Crucially, the as-fabricated sensor, with its remarkable reproducibility, recovery, long-term stability, and anti-interference capabilities, effectively quantified 4-AP, PA, Zn(II) and AA in both pharmaceutical formulations and human plasma samples.