Advanced imidazole-functionalized metal-organic framework-based dual-mode sensor for rapid detection of FLU pesticide residues in food

In this study, an advanced imidazole-functionalized 2D metal-organic framework (HBU-169), {[Cd₂(L)₂H₂O]₂(H₂O)}·(4H₂O)·(DMF) was presented, which possesses both fluorescent properties and oxidase-like activity. HBU-169 demonstrates the ability to detect fluazinam (FLU) via fluorescent and colorimetric modes. In the fluorescent mode, a pronounced fluorescence quenching is observed, with the limit of detection (LOD) of 1.68 μM. The mechanism may involve dynamic quenching process and competitive absorption of excitation energy. The method could be utilized for rapid in-situ imaging detection of pesticide residues on cabbage surface. In the colorimetric mode, a semi-quantitative test paper was developed, featuring visible color changes and smartphone-assisted detection. The mechanism was attributed to the catalytic effect of HBU-169. A high-throughput method combining fluorescent and colorimetric modes were established for FLU detection. This study provides a promising avenue for assessing the safety of FLU-contaminated food and holds potential for application in ensuring the safety of other agricultural products.