Electrochemical Detection of Metronidazole Based on MnMoO₄g-C₃N₄ Modified Electrode

Abstract

 MnMoO₄/g-C₃N₄ nanocomposites were synthesized via a hydrothermal method. The morphology and structure of the composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The MnMoO₄/g-C₃N₄ nanocomposite was coated onto the surface of a glassy carbon electrode (GCE) via a drop-coating method to construct an electrochemical sensor for the detection of metronidazole (MNZ). The electrochemical behavior of the MnMoO₄/g-C₃N₄/GCE electrode was investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The effects of pH value and scan rate on the current response were examined. Under optimized conditions, the sensor exhibited a linear detection range for MNZ from 0.5 to 2400 μmol/L, with a limit of detection (LOD, 3σ/k) of 1.33 nmol/L. The sensor also demonstrated excellent selectivity, stability, and reproducibility. When applied to the detection of MNZ in egg and milk samples, the spiked recoveries ranged from 97.7% to 103.7% and 96.9% to 102.4%, respectively, with relative standard deviations (RSDs) of 1.1%–2.2%. These results indicate that the prepared MnMoO₄/g-C₃N₄/GCE sensor is viable for the detection of MNZ residues in real food samples, providing a novel approach for food safety supervision.