A novel imine-linked covalent organic framework for rapid detection of methyl paraoxon

Methyl paraoxon (MP) has attracted more and more attention in recent years because of its severe neurotoxicity and respiratory toxicity. Therefore, it is very urgent to develop new and sensitive MP detection methods for health protection and public safety. Covalent organic frameworks (COFs) are widely used in fluorescence detection because they can effectively transmit and amplify probe signals with multiple identical binding sites within an extended framework. Here, COFML-DHTA nanosheet material was synthesized by the solvothermal reaction of melem (ML) and 2,5-dihydroxyterephthalaldehyde (DHTA). The resulting COFML-DHTA exhibits remarkable luminescence quenching toward MP due to the relationship of competitive absorption and Forster resonance energy transfer between MP and COFML-DHTA. COFML-DHTA can be used for sensitive and selective detection of MP in a wide concentration range of 0.57 ng mL(-1) to 30 mu g mL(-1) with a detection limit of 0.19 ng mL(-1). The material has good chemical stability, excellent selectivity, good reusability and hydrophilicity, which provide more possibilities for COFs in the detection of pesticides.