A fluorescent detection pen for sensitive, specific, and real-time detection of phosgene based on a novel rhodamine probe

It is of great significance for real-time monitoring of phosgene to protect public safety. In this paper, a new rhodamine derivate with highly rapid, special and sensitive response towards phosgene was synthesized and used as a phosgene probe based on its spirolactam ring-opening property and nucleophilic reaction with phosgene. To realize in situ visualization of phosgene, a fluorescent detection pen with gas-liquid reaction model was proposed for the first time using the mixture of the probe and polystyrene as ink. The detection film could be formed in situ by simply writing on desired surface and respond toward phosgene gas within 30 s with an ultra-low detection limit (2 ppm) with the naked eye. Such a fluorescence pen detection mode supplied a new strategy for the fabrication of an excellent platform for real-time detection of phosgene and other gas analytes.