Sensitive and selective detection of phosgene with a bis-(1H-benzimidazol-2–yl)-based turn-on fluorescent probe in solution and gas phase
As one of chemical weapons in World War I, phosgene (COCl2) is an extremely toxic gas. Due to the widely use in industrial production, phosgene can easily inadvertently leak and pose a serious threat to the environment and human's health and safety. In this study, we first reported a new fluorescent probe (bis-(1H-benzimidazol-2-yl)-methanone) for rapid detection of phosgene. The probe is based on the easily prepared bis-(1H-benzimidazol-2-yl), which can quickly combine with phosgene to obtain a six-membered cyclic carbamylation product and show a state of fluorescence on. The combination of phosgene caused the maximum absorption of Probe 1 shift from 361 nm to 373 nm which showed a color change from colorless to yellow under visible light and meanwhile the strong fluorescence emission peak at 428 nm appeared which showed a color change from no fluorescence to blue-violet fluorescence under UV lamp (365 nm) could be observed. The response of the probe to phosgene has the good properties of fast (within 30 seconds), high selectivity and sensitivity (the detection limit in solution is 3.3 nM). Furthermore, the portable test strips manufactured by the probe can conveniently perform visual and fluorescence detection of phosgene in the gas phase.