A reliable amplified fluorescence-enhanced chemosensor (Eu-MIL-61) for the directional detection of Ag+ in an aqueous solution

Abstract

A robust gallium carboxylate Ga(OH)(btec)·0.5H₂O (MIL-61) was synthesized under mild hydrothermal conditions and selected as the parent MOF to prepare Eu-MIL-61 by post-synthetic modification due to the uncoordinated carbonyl group of the ligand (pyromellitic acid (H4btec)). The firm framework, permanent porosity, and non-coordinated sites make MIL-61 a good scaffold for immobilizing and sensitizing Eu³⁺. The products showed excellent luminescence and, more significantly, Eu-MIL-61 showed excellent selectivity with photoluminescence enhancement, fast response time, and low detection limit for Ag⁺ ions in the aqueous solutions. In addition, the frameworks were not susceptible to the acid–base property of solutions, which can be further applied to monitor the concentration of Ag⁺ in several daily water samples.