▎ 摘　　要

An electrochemical sensor based on graphene sheets (GS)-manganic manganous oxide (Mn3O4)/nafion (Nf) film supported gold nanoparticles (Au) nanocomposites modified gold electrode (GE) was fabricated for selective and sensitive amperometric detection of dopamine (DA) at a low working potential (+0.02 V vs. SCE). The prepared nanocomposites was characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The electrochemical properties of the modified electrode (GE vertical bar GS-Mn3O4/Nf-Au) were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and current-time (i-t curve) method. Under the optimized experimental conditions, the i-t curve showed a linear dependence on DA concentrations ranging from 1.0x10(-6) to 1.3x10(-3) M (R = 0.9985) with a detection limit of 8.0x10(-8) M (S/N = 3). The proposed method was used to detect DA in real pharmaceutical samples using the standard addition method without additional sample pre-treatment with satisfactory results, confirming its promising application in routine DA analysis.