Nanohybrids of shuttle-like α-Fe2O3 nanoparticles and nitrogen-doped graphene for simultaneous voltammetric detection of dopamine and uric acid

Abstract

In this study, an ultrasensitive voltammetric sensor was constructed for the simultaneous detection of dopamine (DA) and uric acid (UA) using shuttle-like α-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 α-Fe₂O₃ with NG nanosheets not only enlarges the electrochemically active surface area and prevents the agglomeration of α-Fe₂O₃ NPs or NG nanosheets, but also increases the electroconductivity of α-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 μM and 10–100 μM, with low detection limits (LOD) of 0.080 and 0.075 μM 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.