Triphenylamine–benzimidazole based switch offers reliable detection of organophosphorus nerve agent (DCP) both in solution and gaseous state.

In this study, a triphenylamine–benzimidazole (TPIM)-functionalised switch has been fabricated for ratiometric recognition of organophosphorus (OP) chemical vapor. Interestingly, upon addition of the nerve agent mimic diethyl chlorophosphate (DCP), a prominent color change from colorless to yellow along with a fluorescence color change from cyan to deep yellow was noticed. The chemodosimeter (TPIM) undergoes tandem nucleophilic substitution reaction with DCP and shows a specific colorimetric and fluorescence alteration. The probe selectively detects DCP over other toxic substituents studied. In addition, the detection limit of TPIM for DCP was found to be in the order of 10−8 M in solution phase using fluorescence method. We have also developed a transportable kit for DCP using our probe (TPIM), which can detect DCP vapour with high sensitivity. [ABSTRACT FROM AUTHOR]