Simultaneous determination of chloramphenicol and tinidazole by electrochemical analysis using MnO2/electrochemically reduced graphene oxide modified electrode

Manganese (IV) oxide/electrochemically reduced graphene oxide (MnO2/ErGO) composite was synthesized in an oxidation-reduction process followed by electrochemical reduction. The obtained materials were characterized with X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) with energy-dispersive X-ray mapping (EDX mapping). The electrochemical reduction of a manganese dioxide/GO film pre-cast on a glassy carbon electrode to rGO was performed by using the chronoamperometric method for preparing the MnO2/ErGO modified electrode. The obtained modified electrode was employed to simultaneously determine chloramphenicol (CAP) and tinidazole (TNZ) with linear sweep adsorptive cathodic stripping voltammetry (LS-AdCSV). The effect of experimental parameters, e.g., potential and time of accumulation, pH of the buffered solutions, and the potential sweep rate on the response, was examined. Under the optimal conditions, the modified electrode shows a wide linear response for the concentration of CAP and TNZ in the range of 0.1–20 μM with a detection limit of 0.58 and 0.33 μM. The practicability of the developed sensor was explored by detecting CAP and TNZ individually or simultaneously in honey, eye drops, and tablet samples with satisfactory results.