▎ 摘　　要

A composite material obtained by ultrasonication of graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) was loaded with manganese dioxide (MnO2), poly(diallyldimethylammonium chloride) and gold nanoparticles (AuNPs), and the resulting multilayer hybrid films were deposited on a glassy carbon electrode (GCE). The microstructure, composition and electrochemical behavior of the composite and the modified GCE were characterized by transmission electron microscopy, Raman spectra, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The electrode induces efficient electrocatalytic oxidation of dopamine at a rather low working voltage of 0.22 V (vs. SCE) at neutral pH values. The response is linear in the 0.5 mu M to 2.5 mM concentration range, the sensitivity is 233.4 mu A center dot mMaEuro3/4(1)center dot cmaEuro3/4(2), and the detection limit is 0.17 mu M at an SNR of 3. The sensor is well reproducible and stable. It displays high selectivity over ascorbic acid, uric acid and glucose even if these are present in comparable concentrations.