Development of AgVO3/PPy/N@rGO composite sensor for efficient electrochemical monitoring of levofloxacin in human fluids and environmental samples

Abstract

In the present work, we developed a low-cost and portable nanocomposite material comprising of silver vanadate/polypyrrole/nitrogen doped reduced graphene oxide (AgVO₃/Ppy/N@rGO) for detection of levofloxacin (LFX) is reported for the first time. The surface morphology of AgVO₃/Ppy/N@rGO was investigated using transmission electron microscopy (TEM). which revealed a distinct rod-like structure for AgVO₃, while the incorporation of Ppy (sphere structure) and N@rGO into the composite resulted in a more complex morphology with well-dispersed rod structures embedded within a matrix of Ppy and N@rGO. This structural modification enhanced the surface area and facilitated better electron transfer, contributing to improved electrochemical performance for LFX sensing. The X-ray crystallography (XRD) patterns of the synthesized AgVO₃/Ppy/N@rGO composites were analyzed to confirm the crystalline structure and phase composition. X-ray photoelectron spectroscopy (XPS) confirmed the presence of key elements (Ag, V, C, N, and O) and demonstrated strong interactions among the components. Under the optimized conditions, AgVO₃/Ppy/N@rGO modified glassy carbon electrode (GCE) was employed to determine LFX using CV and LSV techniques. The developed AgVO₃/Ppy/N@rGO/GCE exhibits robust interfacial interaction and synergistic effect, resulting in an excellent electrocatalytic oxidation response for LFX sensing compared to other electrodes. The AgVO₃/Ppy/N@rGO/GCE displays excellent selectivity even in the presence other co-interferences, and it has two wider linear determination range from 0.5 µmol L⁻¹ - 81.5 µmol L⁻¹ and 96.5 µmol L⁻¹ - 1731.5 µmol L⁻¹ of LFX, with a detection limit (LOD) of 0.0027 µM (S/N=3) and ultra-sensitivity of 240.835 μA μM⁻¹ cm⁻². Moreover, the efficacy of fabricated AgVO₃/Ppy/N@rGO/GCE sensors was examined by analyzing LFX in human fluids and water samples, achieving satisfactory accuracy and recovery. The main advantages of the designed sensor are its simplicity, portability, and affordability.