A novel sensing platform for electrochemical detection of metronidazole antibiotic based on green-synthesized magnetic Fe3O4 nanoparticles.

The spread of antibiotic resistant genes has become a serious global concern. Thus, the development of efficient antibiotic monitoring systems to reduce their environmental risks is of great importance. Here, a potent electrochemical sensor was fabricated to detect metronidazole (MNZ) on the basis of green synthesis of Fe3O4 nanoparticles (NPs) using Sambucus ebulus L. leaves alcoholic plant extract as a safe and impressive reducing and stabilizing agent. Several analyses such as X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS) confirmed the production of homogeneous, monodisperse, regular, and stable magnetite NPs with a spherical morphology. The as-prepared Fe3O4NPs were afterwards applied to evaluate the electrochemical activity of MNZ by merging them with graphene nanosheets (GR NSs) on the glassy carbon electrode (GCE). The GR/Fe3O4NPs/GCE represented extraordinary catalytic activity toward MNZ with two dynamic ranges of 0.05-5 μM and 5-120 μM, limit of detection (LOD) of 0.23 nM, limit of quantification (LOQ) of 0.76 nM, and sensitivity of 7.34 μA μM-1 cm-2. The fabricated sensor was further employed as a practical tool for electrochemical detection of MNZ in real aqueous samples.