Target-induced dissociation of AIE metal-organic framework for fluorescence-enhanced determination of the chlorpyrifos bioaccumulation in wheat by employing Mn (III) as the active center

The extensive application of organophosphorus pesticides (OPs), in agricultural pest management has led to pervasive residue accumulation, posing substantial risks to the environment and human health. This study presented an environmentally friendly approach for chlorpyrifos detection using a Mn(III)-blocked aggregation-induced emission (AIE)-based metal-organic framework (MOF) nanosystem. Attributed to the inhibitory effect of chlorpyrifos on ascorbate oxidase (AAox), ascorbic acid was abundant with the restriction of oxidation by AAox and reduced Mn(III) in MOF. The redox reaction prompted the collapse of MOF and the release of AIEgens. Free AIEgens reassembled into emissive aggregates in the aqueous solution with significantly enhanced fluorescence signal through AIE. The enhanced luminescence enabled the sensitive detection of chlorpyrifos with a detection limit of 3.79 ng mL^-1, as confirmed by recovery tests with food samples. The efficacy of sensor in tracking chlorpyrifos bioaccumulation in wheat underscored the potential for practical application in the residue monitoring within crops. This work introduced a highly sensitive AIE-MOF-based fluorescence sensing and environmentally friendly method for chlorpyrifos detection in crops, which was crucial for ensuring food and environmental safety.