Fluorescent Detector for NH3 based on Responsive Europium(III)–Salicylic acid Complex Hydrogels

Herein, we report an ammonia-responsive of lanthanide (Eu(Sal) 3 , Sal = salicylic acid) complexes hydrogel sensors based on the amine molecule affecting the energy transfer process. In this system, the ammonia stimulation causes the coordination and decomposition of Eu(Sal) 3 in the hydrogel, thus leading the fluorescence quenching and recovery of Sal in the ammonia atmosphere. Furthermore, the EuL n -Fm/PVA hydrogel composed of Eu(Sal) 3 and Eu(TTA) 3 complexes (TTA = 2-Thenoyltrifluoroacetone, L = Sal and TTA, Fm = formamide, n = 1-3) was prepared by an one-pot process, which achieves the continuous detection for ammonia gas. Meanwhile, EuL n -Fm/PVA hydrogel also achieved diverse responses for ammonia gas. This device could be a promising strategy for developing fluorescence hydrogels with potential applications due to its desirable advantages such as simple preparation, cost-effectiveness, etc..