AIE Ligand-Based Luminescent Cd(II)-MOFs for Rapid and Selective Sensing of Pesticide DCN and Practical Application in Vegetable Samples

Food safety issues have become society's focus and have been directly tied to consumer health. In order to guarantee food safety and public health, it was crucial to create innovative food testing methods that were effective, precise, and convenient. Herein, we successfully constructed two new luminescent metal–organic frameworks (MOFs) via solvothermal conditions, designated as [Cd₃(TFBA)₂(DMSO)₂(DIMB)]_n (CdMOF-1) and [Cd₃(TFBA)₂(DMSO)₂(DMIMB)]_n (CdMOF-2) (H₃TFBA = tris(3′-F-4′-carboxybiphenyl)amine, DIMB = 1,4-di(1H-imidazol-1-yl)butane), DMIMB = 1,4-di(1H-2-methylimidazol-1-yl) butane, DMSO = Dimethyl sulfoxide). CdMOF-1 and CdMOF-2 were investigated by single-crystal X-ray analysis and infrared spectroscopy (IR), X-ray powder diffraction (PXRD) and thermal gravimetric analysis (TGA). The fluorescence property studies demonstrated that CdMOF-1 and CdMOF-2 exhibited high selectivity, recyclability, and sensitivity in the detection of 2,6-dichloro-4-nitroaniline (DCN) in actual vegetable samples with low limited detection (LOD) of 0.499 μM, 0.480 μM for CdMOF-1 and 0.308 μM, 0.380 μM for CdMOF-2, respectively. In situ imaging experiment results indicated that CdMOF-1 and CdMOF-2 have the potentiality to quickly and in situ identify pesticide residues on the surfaces of vegetable samples. Interestingly, mixed matrix membranes (MMMs) were also prepared for visual detection of DCN under 365 nm UV light. These findings exhibited that CdMOF-1 and CdMOF-2 could serve as portable luminescent sensors for the detection of DCN.