A ratiometric fluorescent probe based on a dual-ligand lanthanide metal-organic framework (MOF) for sensitive detection of aluminium and fluoride ions in river and tap water

In this study, a ratiometric fluorescent probe towards Al3+ and F- using a lanthanide metal-organic framework material, Eu-BDC-NH2/TDA, is employed, which is composed of a metal centre Eu3+, BDC-NH2 and a TDA dual ligand. This three-dimensional frame structure selectively detects Al3+ and F- with a low limit of detection of 0.14 and 0.46 mu M, respectively, accompanied by a naked-eye identification specificity in the range of 0-1000 mu M. The detection mechanism of Eu-BDC-NH2/TDA towards Al3+ is due to the collapse of the framework and coordination interaction between Al3+ and the ligand, and that towards F- is due to a hydrogen-bond interaction, as evidenced by powder X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and N-2 adsorption-desorption analysis. Furthermore, practical application of Eu-BDC-NH2/TDA is successful for the detection of Al3+ and F- in river and tap water samples.