A novel electrochemical sensor for the detection of metronidazole in honey using the g-C3N4/MnO2/ZnO modified electrode

During beekeeping, the utilization of metronidazole (MNZ) for treating bee ailments leads to the MNZ residues in honey. Prolonged ingestion of honey with MNZ residues could pose potential health hazards to humans. Therefore, the development of a straightforward and efficient MNZ detection method is of utmost importance. ZnO, a non-toxic catalytic material, exhibits promising potential in electrochemical sensor design. The resulting g-C3N4/MnO2/ZnO composite was employed to craft an electrochemical sensor that facilitates swift MNZ quantification in honey. Comprehensive characterization of the synthesized composites was performed, and the electrochemical behavior of MNZ was explored using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the g-C3N4/MnO2/ZnO composite exhibits remarkable electrocatalytic capability, and the resulted sensor demonstrates good sensitivity. Within a range of 2–250 μM, MNZ's current value showed two linear relationships with its concentration, achieving the detection limit of 0.21 μM. When applied to honey samples, the g-C3N4/MnO2/ZnO/GCE sensor detected MNZ with recovery rates spanning 93.7% to 100.3% and relative standard deviations (RSD) under 3%. This attributed to heightened sensitivity, selectivity, repeatability and durability of the sensor. Furthermore, its effectiveness extends to the rapid assessment of MNZ content in actual honey, highlighting its practical utility in identifying MNZ residues in honey.