A europium MOF-based turn-off fluorescent sensor for Cr2O72-, L-tryptophan, Dimethylnidazole detection in water

Various pollutants in water are a serious threat to human health. It is very important to identify and detect harmful substances in water. In this paper, an unprecedented new coordination polymer of luminescent sensor, [[Eu(L)2] Cl center dot H2O] n, (Eu-MOF), with excellent fluorescence sensing abilities for anions, amino acid and antibiotics was developed. It was synthesized by N-heterocyclic carboxylic acid ligands 1, 3-bis (4-carboxylbenzyl) triazole chloride and lanthanide metal ion Eu3+ under solvothermal conditions. The fluorescence results indicate that Eu-MOF has excellent fluorescence sensing abilities for Cr2O72- , L-tryptophan, and Dimethylnidazole via fluorescence quenching. The limit of detection (LOD) is 8.98 x 10-6 mol center dot L-1, 4.94 x 10-5 mol center dot L-1 and 5.50 x 10-5 mol center dot L-1, respectively. Furthermore, the possible mechanisms of fluorescence quenching in the sensing process were systematically studied by UV-vis and DFT. It is revealed that the rational design and utilization of such one multifunctional Eu-MOF can offer guidance for fluorescence detection with wide applications.