Sensitive detection of pesticides by a highly luminescent metal-organic framework

This work reports a highly luminescent metal-organic framework (MOF) with high surface area of 4073.9 m2 g−1, exhibiting an excellent adsorption ability and sensing performance in rapidly detecting parathion-methyl. This is an excellent example of luminescent MOFs to sensitively detect pesticides by fluorescent quenching with satisfactory results. This sensor provides a very wide linear detection range from 1.0 μg kg−1 to 10 mg kg−1, and low limit of detection 0.12 μg kg−1 (0.456 nM) for parathion-methyl. This low detection limit is much lower than the maximum residue limits (MRL) in the European Union pesticides database (0.01 mg kg−1 for fruits and vegetables, 0.02 mg kg−1 for tree nuts), as well as those of previous assays. The quenching effect of parathion-methyl is attributed to the electron-rich chemical group of nitroaromatics which might lead to photo-induced electron transfer. The fluorescent method has been reliably used for the determination of parathion-methyl in spiked irrigation water with satisfactory results, which suggests its potential for rapid detection of pesticides in food and environmental sample.