A highly selective TPE-based AIE fluorescent probe is developed for the detection of Ag

The detection of Ag⁺ in the environment is very important to determine the level of pollution from silver complexes, which have caused various human health problems. Herein, an aggregation-induced emission (AIE) chromophore (tetraphenylethane, TPE) attached to a benzimidazole group (tetra-benzimidazole, TBI-TPE) is synthesized and utilized to detect Ag⁺ in the environment. The strong chelating effect between the benzimidazole group and Ag⁺ leads to the formation of aggregates, and strong yellow fluorescence signals were observed after adding Ag⁺ into a TBI-TPE solution. The stoichiometry of the complex of TBI-TPE and Ag⁺ was established to be 1 : 2 using photochemical and mass spectra measurements. The detection limit of the Ag⁺ assay is 90 nM with a linear range from 100 nM to 6 μM. This study provides a facile method to determine Ag⁺ in real environmental samples with satisfactory results.