PPy/Co₃O₄/MnO₂ Nanoarchitecture as a Biomedical Electrochemical Sensing Platform for Sulfamerazine Monitoring in Clinical and Environmental Matrices

Abstract

This work establishes a robust biomedical electrochemical platform for point-of-care sulfamerazine (SFZ) monitoring (requiring low volume and miniaturized potentiostat) by engineering a hierarchical ternary nanocomposite of polypyrrole, cobalt oxide, and manganese dioxide (PPy/Co₃O₄/MnO₂) on a glassy carbon electrode (GCE). The synergistic integration of the conductive PPy matrix with the electrocatalytic Co₃O₄ nanoparticles and high-surface-area MnO₂ nanorods was supported by through X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS) analyses. This unique architecture enhanced the electroactive surface area (0.172 cm²) and accelerated electron transfer kinetics, as evidenced by a low charge transfer resistance of 6.1 kΩ. The sensor facilitated an adsorption-controlled, irreversible oxidation of SFZ via a 2-electron, 2-proton transfer mechanism, confirmed by scan rate and pH studies. Under optimized Square Wave Voltammetry (SWV) conditions, the sensor exhibited a wide linear range (1-100 µM), a sensitivity of 0.502 µA/µM, and low detection and quantification limits of 0.45 ± 0.03 µM and 0.98 ± 0.05 µM, respectively. The platform demonstrated exceptional selectivity against common interferents and structurally similar drugs, alongside outstanding stability (95.2% signal retention) and reproducibility (RSD < 4.1%). Successful application in tap water, river water, and artificial urine yielded excellent recovery rates (97.1–103.4%), validating its potential for reliable SFZ detection in clinical and environmental monitoring.

Graphical Abstract