Integrated LaFeO3/rGO nanocomposite for the sensitive electrochemical detection of antibiotic drug metronidazole in urine and milk samples

Abstract

Metronidazole (MTZ) is a nitroimidazole antibiotic commonly used to treat bacterial infections, but its residues in food products may pose teratogenic, mutagenic, and carcinogenic risks to human health. Hence, monitoring MTZ in food and human samples is essential. In this study, we developed a glassy carbon electrode (GCE) modified with lanthanum ferrite (LFO) integrated with reduced graphene oxide (rGO) nanocomposite for the electrochemical detection of MTZ. The engineered nanocomposite was prepared by the sonochemical treatment and then systematically characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. The modified LFO/rGO/GCE exhibits excellent electrochemical performance, which is mainly owing to the high surface areas, conductivity, and synergistic effects of LFO and rGO. Using the DPV method, the LFO/rGO/GCE sensor showed a wide linear range of 0.2–1221 µM and a low LOD of 0.048 µM for MTZ detection. The modified sensor selectivity was confirmed with biological species and metal compounds. In addition, the developed sensor demonstrated good stability, reproducibility, and repeatability toward MTZ. Satisfactory recoveries were obtained for MTZ detection in human urine and milk samples using the fabricated LFO/rGO/GCE sensor.