Fluorometric detection of volatile amines using an indanonalkene platform

Abstract

Excessive volatile amines are considered to cause environmental pollution and harm to human health, and especially, ammonia has been reported to be associated with a variety of human diseases. In this article, we developed a gas sensor named CA-SCH₃ based on an indanonalkene structure, for real-time/on-site and quantitative detection of volatile amines. The non-luminescent probe containing a bis-vinylogous thioester receptor exhibited high reactivity towards volatile amines, e.g., ammonia, via an amine–thiol scrambling reaction. A turn-on fluorescence signal and a blue shift in the UV-vis absorbance signal were observed for this chemosensor in the presence of ammonia. A paper-based gas sensor loaded with the probe exhibited fluorescence enhancement for the quantification of ammonia gas. Volatile amines from fish spoilage were also captured and detected via the paper sensor. Furthermore, we prepared a polyethylene glycol film interlinked by the CA-SCH₃ reagent which exhibited a dual response of macroscopic degradation and fluorescence readout towards ammonia vapors. The fluorescent probe (CA-SCH₃) with a novel amine receptor offers extensive possibilities for developing additional photoluminescent detection systems.