▎ 摘　　要

In this study, an ultrasensitive voltammetric sensor was constructed for the simultaneous detection of dopamine (DA) and uric acid (UA) using shuttle-like alpha-Fe2O3 nanoparticle/nitrogen-doped graphene nanocomposites (Fe2O3-NG). The surface morphologies, crystalline structures, and electrochemical properties of Fe2O3-NG were investigated by scanning electron microscopy, powder X-ray diffraction, cyclic voltammetry, and AC impedance spectroscopy. Coupling shuttle-like alpha-Fe2O3 with NG nanosheets not only enlarges the electrochemically active surface area and prevents the agglomeration of alpha-Fe2O3 NPs or NG nanosheets, but also increases the electroconductivity of alpha-Fe2O3 NPs and boosts its catalytic ability, thereby affording more electroactive sites for the adsorption and oxidation of target analytes. As expected, the Fe2O3-NG/GCE shows extraordinary electrocatalytic oxidation capacities toward DA and UA over two wide dynamical response concentration ranges of 0.5-10 mu M and 10-100 mu M, with low detection limits (LOD) of 0.080 and 0.075 mu M for DA and UA, respectively. Moreover, the Fe2O3-NG/GCE shows high anti-interference ability against several potential interferences and retains stable voltammetric responses for at least a week. Finally, the Fe2O3-NG/GCE achieves the simultaneous determination of DA and UA in human serum with reliable results.