A Ratiometric Benzimidazole-Based Fluorescent Probe for The Recognition of Phosgene in Solution and Gaseous Phases

Considering the high toxicity and widespread application of phosgene, there is an urgent need to develop a simple and sensitive method for detecting phosgene. In this work, we designed and synthesized a novel ratiometric fluorescent probe 1 containing fluorophores of benzimidazole and benzothiazole. Probe 1 showed excellent sensitivity (< 30 s) and selectivity (LOD = 3.82 nM) for phosgene and significant ratiometric fluorescence changes. In addition, 1-loaded polystyrene membrane test strips were used to conveniently and efficiently detect phosgene gas (0.5 ppm) via the naked eye and the RGB APP of the smartphone, indicating that this probe has great potential for phosgene detection in the gaseous phase.