Department of Chemistry , University of Science and Technology of China , Hefei 230026 , P. R. China.
Anal Chem. 2019 May 7;91(9):5690-5697. doi: 10.1021/acs.analchem.8b05777. Epub 2019 Apr 25.
As highly toxic and accessible chemical reagents, phosgene and triphosgene have become a serious threat to public safety. So, it is highly desirable to develop facile methods to detect and recognize them. In this article, a novel fluorescent chemosensor, Phos-4, has been constructed with 1,8-naphthalimide as the fluorophore and 2-(2-aminophenyl)imidazol as the recognition sites for discrimination between phosgene and triphosgene in a dual-channel mode for the first time. Owing to the difference in electrophilicity between chlorocarbonyl and trichloromethoxycarbonyl, the sensing reaction of Phos-4 with phosgene undergoes two carbamylations to afford a cyclic product with green fluorescence, and only one carbamylation occurs for triphosgene to form a noncyclic product with blue fluorescence. The sensor Phos-4 exhibits high sensitivity (the limit of detection, 3.2 nM, for phosgene, and 1.9 nM, for triphosgene) and high selectivity in solutions. Furthermore, facile test papers containing Phos-4-embedded nanofibrous membrane have been fabricated by the electrospinning technology. The test papers can provide visual and selective detection of phosgene with a lower limit of detection (42 ppb) and a faster response (≤10 s) in the gas phase over those in solutions. The test paper with Phos-4 is promising to be a practical detection tool of gaseous phosgene.
光气和三光气作为高毒性且易获取的化学试剂，对公共安全构成了严重威胁。因此，开发简便的方法来检测和识别它们是非常有必要的。本文首次构建了一种新型荧光化学传感器 Phos-4，以 1,8-萘酰亚胺为荧光团，2-(2-氨基苯基)咪唑为识别位点，以双通道模式对光气和三光气进行区分。由于氯羰基和三氯甲氧基羰基的亲电性不同，Phos-4 与光气的传感反应经历两次氨甲酰化，生成具有绿色荧光的环状产物，而三光气仅发生一次氨甲酰化，形成具有蓝色荧光的非环状产物。传感器 Phos-4 在溶液中表现出高灵敏度（对光气的检测限为 3.2 nM，对三光气的检测限为 1.9 nM）和高选择性。此外，通过静电纺丝技术制备了含有 Phos-4 嵌入式纳米纤维膜的简易试纸。该试纸在气相中对光气具有较低的检测限（42 ppb）和更快的响应时间（≤10 s），具有比溶液中更好的选择性。含有 Phos-4 的试纸有望成为一种实用的气态光气检测工具。
