Europium metal-organic frameworks: Synthesis, characterization, and application as fluorescence sensors for the detection of Cu2+, Ni2+ cations and T3, T4 hormones

The solvothermal approach was used to create a novel Eu metal-organic framework (Eu-MOF) based on 1,4-benzendicarboxylic acid (TPA), 1,10-phenanthroline, and N,N-dimethylformamide (DMF)/H2O. Structural analysis of Eu-MOF, Fluorescence spectrometry, Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDX) mapping, Thermo-gravimetric analysis (TGA), and Single Crystal X-Ray Diffraction (PXRD) methods. Using the fluorescence properties of the synthesized Eu-MOF, its use as a fluorescence sensor in the determination of different analytes, such as organic molecules (T3-T4 hormone, ascorbic acid, and glucose) and metal ions (Na+, K+, Ca2+, Mg2+, Cu2+, Mn2+, Hg2+, Pb2+, Ni2+, Cr3+, Al3+, Fe3+), was investigated. Fluorescence experiments revealed that Cu2+, Ni2+ cations, as well as T3 and T4 hormones, quenched the fluorescence of Eu-MOF. Turn-off luminescence can be induced by 10 μM Cu2+, 30 μM Ni2+ cations, 500 nM T3, and 800 nM T4 hormones. Fluorescence quenching efficiencies were calculated for Cu2+, Ni2+, T3, and T4 99.7%, 99.6%, 98.7%, and 98.2%, respectively.