Enhanced Electrocatalytic Activity of ZIF-67C/CuO-NiO Composite for the Sensoring of Nitrite in Food

An enhanced electrocatalytic composite-ZIF-67C/CuO-NiO was prepared via hydrothermal and calcination method, and the ZIF-67C/CuO-NiO/GCE was constructed for the identification of nitrite in foods. The morphology and structure of ZIF-67C/CuO-NiO composite was characterized by X-ray diffraction and scanning electron microscopy. The construction process of the modified electrode was characterized by electrochemical impedance spectroscopy and cyclic voltammetry techniques. The electrocatalytic performance of different modified electrodes for nitrite were investigated through i-t curve. The experimental results indicated that the ZIF-67C/CuO-NiO/GCE showed a good electrocatalytic ability for nitrite, and the current change was proportional to the concentration of nitrite. The linear range (LR) was 0.2~125 µM (R1 = 0.9981) and 125~455 µM (R2 = 0.996), and the detection limit was 0.073 µM. The proposed method was successfully applied to determinate nitrite content in ham sausage and small dried fish, and the recovery rate was between 96.17% and 105.43%, indicating satisfactory method performance.