▎ 摘　　要

A novel ultrasensitive modified electrode was fabricated with a graphene nanosheets and carbon nanospheres (GNS-CNS)-based nanocomposite film as a powerful platform. Pt nanoparticles (PtNPs) were simply electrodeposited onto the GNS-CNS-coated glassy carbon electrode creating a PtNPs/GNS-CNS hybrid nanocomposite modified electrode. Scanning electron microscopy, energy dispersive X-ray spectroscopy and linear sweep voltammetry (LSV) techniques were used for the characterization of the prepared modified electrode. The results of investigation of electrochemical response characteristics of cefepime (CP) revealed a considerable improvement in the oxidation peak current of CP on PtNPs/GNS-CNS/GCE compared to GNS-CNS/GCE or PtNPs/GCE. The observation of a synergistic effect between GNS-CNS and PtNPs is related to the electroactivity enhancement of PtNPs in the constructed nanostructured composite due to high electron-transfer ability of GNS-CNS. Under optimal conditions, the modified electrode showed high sensitivity (b(CP) = d/(p,a)(CP)/d[CP] = 1747.2 nA nM(-1)), a low detection limit (LOD (CP) = 1.2 nM, S/N = 3) and a wide linear dynamic range (8 nM to 6 mu M) for the voltammetric determination of CP. The prepared electrode was successfully applied for the accurate determination of trace amounts of CP in pharmaceutical and clinical samples.