Smartphone-assisted detection of organophosphorus pesticides (OPs) in juice drinks and fruits based on cerium-based nanozyme

A new cerium-based nanozyme (Bpy Ce) with high organophosphorus hydrolase-like activity was simply prepared. A sensing platform free of natural enzymes was constructed for the selective detection of organophosphorus pesticides (OPs) in juice drinks and fruits, based on both absorbance measurements and smartphone-assisted RGB value extraction. The synthesis method of Bpy-Ce was simple, structurally stable, and had good organophosphorus hydrolase-like activity. Fenitrothion was hydrolyzed to yellow 3-methyl-p-nitrophenol through hydrolysis of the P O bond. This hydrolysis process can be directly judged visually. Therefore, not only were the absorbance values used to determine the yellow hydrolyzed product of fenitrothion, but also the color of the product in the picture was preserved through smartphone-assisted methods. The RGB values of the colors in the image were extracted, and the R, G, and B values were added. These methods can detect the corresponding concentration of fenitrothion in juice drinks. The colorimetric sensing platform exhibited excellent performance for point-of-care detection (POCT) of real samples. And the detection limit of Bpy-Ce nanozyme for fenitrothion has reached 0.022 μg/mL. Free of natural enzymes fenitrothion sensing platform exhibited selective and robust anti-interference capability, providing a new strategy for selective point-of-care detection of OPs.