An Aggregation-Induced Emission-Based "Turn-On" Fluorescent Probe for Facile Detection of Gaseous Formaldehyde.

Gaseous formaldehyde (FA), a common indoor pollutant, presents a serious threat to human health. As an efficient tool for FA detection, fluorescent probes exhibit the advantages of low cost, ease of use, facile operation, etc. However, previously developed FA fluorescent probes are mostly based on fluorophores with aggregation-caused quenching features and thus require dispersion in solvent to detect FA. In this study, a fluorescent probe (TPE-FA) based on an aggregation-induced emission (AIE) fluorophore (tetraphenylethylene) has been developed for facile detection of gaseous FA through a fluorescence "turn-on" response. TPE-FA reacts with FA through 2-aza-Cope sigmatropic rearrangement. Based on the AIE features of TPE-FA, we fabricated a portable solid sensor, FA test plate, by directly loading TPE-FA on high performance thin-layer chromatography silica gel plate. The FA test plate achieved sensitive, selective, and quantitative detection of gaseous FA. The detection limit (0.036 mg/m3) of the FA test plate is lower than the air quality guideline value of gaseous FA (0.1 mg/m3) recommended by WHO. As a solid sensor for gaseous FA, the FA test plate based on AIE molecule is portable, which enables safer and more convenient use and transport compared to solution-based sensors.