Sustainable electrochemical detection of catechol using a CuO@Polyaniline Nanocomposite: optimization and analytical performance via Box–Behnken design

A copper oxide-based polyaniline nanocomposite (CuO@PANI) was used to modify a glassy carbon electrode (GCE) in order to create an electrochemical sensor, synthesized via in situ oxidative polymerization. The methods of Fourier transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) area of measurement analysis and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX) were used to thoroughly characterize the composite, including elemental mapping. These characterizations confirmed enhanced structural integrity, increased surface area and improved electrical conductivity arising from the presence of CuO nanoparticles and polyaniline. Electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were used to assess the improved electrode’s electrochemical performance, demonstrating significantly enhanced electron transfer kinetics and excellent electrochemical responsiveness. Box-Behnken methodology was used for the simultaneous optimization of the main experimental variables, therefore the optimal conditions were pH: 7.18, casting solution volume: 13 µL, drying time: 3.25 h, and accumulation time: 4.49 min. DPV measurements, after optimization, showed excellent sensitivity (17.823 A/M) and a broad linear range (0.001-10 µM) with a low limit of detection of about 1 nM. Interference and recoveries (98%-103%) tests confirmed the outstanding properties of the proposed sensor and the possibility to be used in real application for catechol contamination in environmental applications.