Zn-ZrMOF containing Lewis acid-base catalytic sites for hydrolysis and visual detection of profenofos

A colorimetric method for the catalysis hydrolysis of profenofos (C11H15BrClO3PS) was designed based on Zn-ZrMOF. Zn-ZrMOF has the catalytic activity of organophosphorus hydrolase and contains Lewis acid-base catalytic sites, which can catalyze the cleavage of P-O bond of profenofos to obtain hydrolysate (4-bromo-2-chlorophenol). As a phenolic substance, 4-bromo-2-chlorophenol can react with the chromogenic agent 4-aminoantipyrine (4-AAP) and produce a pink product (4-((3-chloro-4-oxocyclohexa-2,5-dien-1-ylidene)amino)− 1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one) in the presence of oxidizer K3[Fe(CN)6] under the weak alkalinity. The pink product has a strong UV absorption peak at 508 nm. The solution color gradually changed from colorless to pink with the increase of the concentration of profenofos. The concentration of profenofos could be semi-quantitatively analyzed by naked eye. The linear range of this method was 0.01–1000 μg mL−1, and the detection limit was 6.33 × 10−3 μg mL−1. Additionally, the method has good selectivity and accuracy for the determination of profenofos. This study provides a feasible strategy for the design of a metal-organic framework material with organophosphorus hydrolase-like catalytic activity for the determination of profenofos in vegetables.