A luminescent Tb3+ cholate hydrogel-based multi-functionalized platform for Hg2+ and NO2 detection

Abstract

In this study, a luminescent Tb³⁺ cholate hydrogel (Tb³⁺/hydrogel) system was selected as a multi-functionalized platform, and PS-BD@Tb³⁺/hydrogel or PS-BS@Tb³⁺/hydrogel systems were fabricated for the selective detection of Hg²⁺ in water and NO₂ in air by doping 2-biphenyl-4-yl-1,3-dithiolane (PS-BD) or 4-[[[(1,1-dimethylethyl)dimethylsilyl]oxy]methyl]-1,1′-biphenyl (PS-BS) with the Tb³⁺/hydrogel. Based on the Hg²⁺-catalyzed deprotection of mercaptans and the oxidative splitting of the siloxane ether compound of NO₂, 4-phenylbenzaldehyde (S-PB) can sensitize Tb³⁺ and produce strong green luminescence (the “antenna effect”) in the Tb³⁺/hydrogel environment. In addition, a portable smartphone detection platform for Hg²⁺ and NO₂ was realized online via Bluetooth for the luminescence color changes, and the results are consistent with the luminescence assay results. A chitosan non-woven fabric was coated with the PS-BD@Tb³⁺/hydrogel and used to evaluate the efficient capture and removal of Hg²⁺ in actual water samples.