▎ 摘　　要

Dopamine determination has become crucial as the abnormal levels of dopamine can potentially cause psychological disorders as well as Parkinson's disease. Herein, a novel electrochemical sensing platform based on magnetite (Fe3O4), silver nanoparticles (AgNPs) and reduced graphene oxide (rGO) composite, denoted as rGO-Fe3O4/AgNPs was facilely synthesized using a modified Hummer's two-step synthesis and co-precipitation approach without the use of any other oxidants or stabilizers. This composite was designed as an electrochemical sensor for exceptionally sensitive DA detection in human urine samples. The microscopic study of the composite revealed that the Fe3O4 and AgNPs were extensively decorated onto the rGO surface. The optimized scan rate of 100 mV s(-1) and neutral pH of the supporting electrolyte for the composite-modified electrode was further used to determine dopamine (DA) in human urine samples. DA displayed an anodic peak at 0.20 V vs Ag/AgCl (3.0 mol l(-1) KCl) utilizing differential pulse voltammetry technique. With detection limits of 3.98 nM, the analytical curves obtain a wide range of linear from 0.015 mu M to 100 mu M. The designed sensor had several advantages, including ease of preparation, low cost of nanomaterials utilized, and rapid response.