An effective fluorescent probe for detection of phosgene based on naphthalimide dyes in liquid and gaseous phases

A fluorescent probe was developed for the detection of phosgene based on 1,8-naphthalimide, of which o-diaminobenzene was used as the recognition moiety. The probe does not fluoresce due to nonradiative decay. The probe reacts rapidly with phosgene via an intramolecular cyclization reaction, which induces large fluorescence due to increased rigidity in the resulting molecule and a low detection limit (0.23 nM). This probe has excellent selectivity for phosgene against competing interference analytes and, in the form of probe-loaded test paper, is an extremely sensitive method for phosgene sensing in the gas phase below 1 ppm concentrations.