▎ 摘　　要

To date, numerous chemical substances are existing in food products, which cause some health issues in humans. Monitoring and controlling the level of toxicity in food for daily life is an important one. Hence, rapid and inexpensive detection methods are developed for the quantification of toxic chemicals. As a consequence, we have chosen the electrochemical sensing method for the detection of food toxicant diphenylamine (DPA). Herein, the flake-like structured nickel phosphate (NPO) is synthesized using the coprecipitation method and the preparation of NPO integrated graphene oxide (GO) by sonochemical treatment. As observed from electrochemical impedance spectra (EIS) analysis, the NPO/GO modified screen-printed carbon electrode (SPCE) has a lower charge transfer resistance (Rct) of 624 ohm and a fast electron transfer rate. The higher catalytic activity of NPO combined with a higher conductive and active surface area of GO through the electrostatic interaction is applied for the electrochemical determination of DPA. Using the differential pulse voltammetry (DPV) technique, the constructed NPO/GO/SPCE has a broad linear range (0.4 -680.8 mu M), low LOD (12 nM), and good sensitivity (1.01 mu A mu M-1 cm-2) towards DPA sensing. Furthermore, the resultant sensor revealed good selectivity, cyclic and storage stability, repeatability, and reproducibility. The practical application of the DPA was estimated in food samples such as apple, grapes, and orange juice with satisfactory recovery.