Abstract
Various morphologies of iron oxide nanoparticles (Fe2O3 NPs), including cubic, thorhombic and discal shapes were synthesized by a facile meta-ion mediated hydrothermal route. To further improve the electrochemical sensing properties, discal Fe2O3 NPs with the highest electrocatalytic activity were coupled with graphene oxide (GO) nanosheets. The surface morphology, microstructures and electrochemical properties of the obtained Fe2O3 NPs and Fe2O3/GO nanohybrids were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. As expected, the electrochemical performances were found to be highly related to morphology. The discal Fe2O3 NPs coupled with GO showed remarkable electrocatalytic activity toward the oxidation of dopamine (DA) and uric acid (UA), due to their excellent synergistic effect. The electrochemical responses of both DA and UA were linear to their concentrations in the ranges of 0.02–10 μM and 10–100 μM, with very low limits of detection (LOD) of 3.2 nM and 2.5 nM for DA and UA, respectively. Moreover, the d-Fe2O3/GO nanohybrids showed good selectivity and reproducibility. The proposed d-Fe2O3/GO/GCE realized the simultaneous detection of DA and UA in human serum and urine samples with satisfactory recoveries.
Highlights
Dopamine (DA) and uric acid (UA) usually coexist in the serum and extracellular fluids of the central nervous system and play a significant role in regulating human metabolism activity [1]
The rapid and reliable detection of DA in physiological samples remains critical and challenging due to the low DA concentration in the extracellular matrix and its susceptibility to interference from endogenous substances such as UA and ascorbic acid (AA)
Since DA and UA usually coexist in physiological fluids, it is of the utmost importance to propose a highly efficient technique for the simultaneous determination of DA and UA
Summary
Dopamine (DA) and uric acid (UA) usually coexist in the serum and extracellular fluids of the central nervous system and play a significant role in regulating human metabolism activity [1]. The rapid and reliable detection of DA in physiological samples remains critical and challenging due to the low DA concentration in the extracellular matrix (usually in the range of 0.01–1 μM) and its susceptibility to interference from endogenous substances such as UA and ascorbic acid (AA) Uric acid is another crucial biomolecule in physiological fluids and is often regarded as the end-product of purine metabolism in the human body [6]. The electrochemical sensing performances of pure α-Fe2O3 NPs modified electrodes are relatively poor probably because of their poor electrical conductivity and dispersibility [37,53,54] To address this issue, iron oxides were often used in a composite with graphene for the detection of DA. A novel and ultrasensitive electrochemical sensor based on d-Fe2O3/GO nanohybrids was proposed for the simultaneous detection of DA and UA
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