A highly chemical stable Eu6-cluster-based ftw-MOF for highly luminescent sensitive detection of metal ions and antibiotics in aqueous solution.

A luminescent Eu-MOF was constructed with an amide-functionalized tetracarboxylate ligand and featured a hexanuclear metal cluster [Eu6(μ3-OH)8(COO)12(H2O)6], which was further connected with organic linkers to assemble the final (4,12)-connected ftw network. The high-nuclear metal clusters endowed the resultant high connected framework with excellent chemical robustness in acidic/basic solutions within the wide pH range of 1.67 to 12.30. Consequently, Eu-MOF can be exploited as a promising multi-probe capable of simultaneously detecting Fe3+ and two antibiotics, metronidazole (MDZ) and dimetronidazole (DTZ), in aqueous solutions. Even in the simulated biological buffer solution HEPES, Eu-MOF still demonstrated excellent quenching recognition ability for Fe3+ with Ksv of 1.2 × 104 M-1. Eu-MOF-based test paper can be developed to provide a simple and reliable method for the detection of MDZ/DTZ. Moreover, the at least nine-cycle detection capability of Eu-MOF for MD/DTZ further highlights the true application potential of this sensor. In all, the high chemical stability, excellent fluorescence sensing ability and at least nine-cycle reusability with outstanding framework robustness of Eu-MOF may spark the real application prospects of this promising multi-sensor in detecting metal ions and antibiotics in actual biological systems.