A ratiometric fluorescence platform based on bifunctional MOFs for sensitive detection of organophosphorus pesticides

Rapid and precise detection of organophosphorus pesticides (OPs) is of great importance for life health. Herein, a new sensing platform is developed through a dual signal amplification approach for sensitive quantification of OPs, with a bimetallic metal organic framework (UiO-66(Zr/Fe)-NH 2 ) as peroxide-like nanozyme and fluorescent indicator. In the presence of thiocholine (TCh), the hydrolyzate of acetylthiocholine iodide catalyzed by acetylcholinesterase, the catalytic oxidization of o-phenylenediamine by UiO-66(Fe/Zr)-NH 2 to strong fluorescent 2,3-diaminophenazine (λ em 555 nm) is significantly inhibited. OPs-triggered acetylcholinesterase inactivation enables the renaturation of UiO-66(Fe/Zr)-NH 2 . Interestingly, the introduction of 1,4-dioxane further boosts the amplification of fluorescence signals. By virtue of the recovered fluorescence at 555 nm and MOF fluorescence (λ em 446 nm), the dual signal amplification-based ratiometric fluorescent platform is successfully employed for the selective recognition and sensitive detection of OPs. This work is expected to provide a facile and sensitive method for accurate OPs assay, and make a positive contribution to food safety.