▎ 摘　　要

In this study, the Pt nanoparticles/over-oxidized polypyrrole nanofiber/reduced graphene oxide (Pt NPs/OPPy/RGO) nanocomposite was electrochemically synthesized and used to modify a glassy carbon electrode. To confirm the Surface morphology and characterization of the nanocomposite, field emission scanning microscopy (FE-SEM), X-ray diffraction (XRD), Raman, FT-IR, and X-ray photoelectron spectroscopy (XPS) were used. Simultaneous determination of these species showed one linear response 0.1-250.0 mu M and two linear responses 0.5-10.0 mu M and 10.0-470.0 mu M, with detection limits 42 nM and 106 nM (S/N = 3) for DA and 5-HT, respectively. Finally, the analytical application of this modified electrode was investigated in the human blood plasma.