A novel colorimetric strategy for rapid detection of dimethoate residue in vegetables based on enhancing oxidase-mimicking catalytic activity of cube-shape Ag2O particles

Although many colorimetric methods have been established for pesticide analysis, most of them rely on inhibiting catalytic activities of natural enzymes or nanozyme , easily leading to false positives in results of pesticide detection. Herein, a simple, stable, and rapid colorimetric method was firstly proposed to detect pesticide residues in vegetables based on enhancing the oxidase-mimicking activity of cube-shape Ag 2 O. The experiments, including fluorescence probe, electrochemistry , free radical tracking and enzymatic kinetics, confirmed that dimethoate could promote electron transfer from Ag 2 O to dissolved oxygen and accelerate the release of·O 2 - radicals as well as 1 O 2 , facilitating the catalytic oxidation of the chromogenic substrate. The colorimetric method exhibited satisfactory sensitivity with the limit of detection as low as 14 μg·L −1 . Moreover, such method showed excellent selectivity against other competitive pesticides, and achieved good recovery in several typical vegetables, which indicate that such strategy has a bright application prospect in the field of pesticide detection in food.