Abstract
In this study, a novel nanomaterial obtained through high-temperature carbonization of petroleum coke was combined with copper oxide nanoparticles Coke-Derived Carbon@Copper(II) Oxide Nanoparticles (CDC@CuO-NPs) to develop a non-enzymatic electrochemical sensor for the indirect detection of malathion. To the best of our knowledge, this is the first report utilizing coke-derived carbon as a conductive support for CuO-based inhibition-type sensing of malathion. The obtained coke-derived carbon nanocomposite provided high conductivity and a large surface area, enabling uniform dispersion of CuO nanoparticles. SEM analysis confirmed the successful integration of CuO within the CDC matrix. The strong interaction between malathion and CuO resulted in significant suppression of the CuO redox signal, forming the basis of an inhibition-type sensing mechanism. Electrochemical performance was evaluated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The sensor showed a linear response to malathion concentrations ranging from 2.0 to 10.0 nM with a low detection limit of 0.05 nM (S/N = 3) under optimized conditions. The CDC@CuO-NPs-CS/GCE sensor demonstrated excellent stability, reproducibility, and selectivity, and was successfully applied to real water samples with recoveries of 99.13–102.3%. These findings highlight the potential of the proposed sensor as a cost-effective and highly sensitive platform for environmental monitoring of organophosphorus pesticides.