Direct electrochemical enhanced detection of dopamine based on peroxidase-like activity of Fe3O4@Au composite nanoparticles

摘要

Substantially, the unique enzyme-like bioactivity of nanoparticles is essential for the detection performance promotion of electrochemical sensors. Herein, the gold magnetic particles (Fe3O4@Au) were successfully formed by self-assembly method, its physical and chemical properties are characterized by Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) techniques. Fe3O4@Au was found to be able to exhibit impressive peroxidase-like activity and follow Michaelis-Menten kinetics with a good affinity towards H2O2 and TMB. A novel highly sensitive and selective enzyme-free enhanced electrochemical sensor based on the peroxidase-like activity of Fe3O4@Au was prepared for the detection of dopamine (DA). Electrochemical cyclic voltammetry (CV) was used to measure dopamine and the electrochemical detection system was optimized. The results showed that the established enzyme-free enhanced electrochemical sensor showed extremely high sensitivity towards dopamine under the optimized conditions, with a good linear relationship between the current response, and the concentration of dopamine in the range of 0.01?1 mmol/L with a detection limit of 0.0109 mg/L (S/N = 3). In addition, the established enzyme-free enhanced electrochemical sensor was successfully applied in the detection of dopamine in pork samples. In view of this, the proposed new enzyme-free electrochemical assay has great potential in the fields of food quality control and security detection.