A new fluorescent probe for ultrasensitive detection of phosgene in solution and the gas phase

Abstract

Due to the high toxicity and commercial availability of phosgene, it is urgent to detect phosgene quickly and reliably to deal with its potential serious threat to public safety. A new 2-(2-aminophenyl)quinazolin-4(3H)-one (APQ) based fluorescent probe APQ has been developed as a rapid, highly sensitive, and selective sensor for phosgene in this work. APQ displays very weak fluorescence in acetonitrile due to the free rotation of the 2-aminophenyl moiety. After reacting with phosgene, APQ is converted to a new restricted intramolecular motion product APQU1. Owing to the specific cyclization reactions, APQ exhibits an obvious fluorescence response toward phosgene with a large Stokes shift (104 nm), instant response (less than 20 s), and low detection limit (0.16 ppm). Moreover, the APQ-loaded test strip was prepared and demonstrated to have practical utility in detecting phosgene vapor.