Highly Sensitive and Selective Nonenzymatic Sulfite Sensor Based on LaFeO3/Graphene

LaFeO3 was synthesized by sol-gel method, and corresponding LaFeO3/graphene composite materials were prepared under the condition of ultrasonic dispersion. The as-prepared composite modified electrode was used as electrochemical sensor to detect sulfite content. The morphology, structure and elemental composition of the prepared composite were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray electron spectroscopy (XPS). A group of electrochemical properties of the optimal LaFeO3 were investigated by differential pulse voltammetry (DPV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical test results showed that the LaFeO3/graphene composite modified electrode has a good response signal for sulfite. Its response current is proportional to the concentration of sulfite in the range of 1 ~ 200 μM. The linear relationship is I(μA) = 0.119 C(μM) + 0.135. Correlation coefficient (R2) is 0.994, and the limit of detection (LOD) (S/N = 3) is 0.21 μM. The proposed method was successfully applied to white wine samples, the recovery rate is within the range of 97.63% to 103.02% (n = 5). Therefore, the as-prepared sulfite sensor has the characteristics of high sensitivity, low LOD, good stability and reproducibility, and good anti-interference ability.