An instantaneously-responded, ultrasensitive, reutilizable fluorescent probe to sarin substitute both in solution and in gas phase.

• A novel conjugated polymer (P1) as probe to detect Sarin substitute DCP. • P1 is used as a dual-channel probe to DCP solution and the LOD is as low as 2.3 nM. • P1 film presents rapid response, high sensitivity and selectivity to DCP vapour. • P1 filter paper strip is used to detect DCP vapour and the LOD is as low as 0.7 ppb. • P1 realizes the properties recovery by adding water in solution and in gas phase. A novel 4 H -1, 2, 4-triazole (TAZ)-based conjugated polymer (P1) is reported as highly efficient probe to Sarin substitute Diethylchlorophosphate (DCP) both in solution and in gas phase, which featured rapid response, high sensitivity and selectivity and good reusability. The chemosensor displays obvious fluorometric and colorimetric dual-channel responses toward DCP solution and the limit of detection (LOD) is as low as 2.3 nM. Upon the exposure to DCP vapour, P1 film shows an instantaneous fluorescent red-shifted response (from 440 nm to 500 nm), accompanying the emission colour changes from blue to green. Furthermore, its filter paper strip is prepared for in-situ and real-time practical detection of DCP vapour. Even more remarkably, semiquantitative fluorescence cards based on P1 filter paper strips are also developed to visually detect DCP vapour and the LOD is as low as 0.7 ppb. What should be noted is that this chemosensor could realize the fluorescence/colour recovery by adding water not only in solution but also in gas phase, which endows this chemosensor promising application prospect. [ABSTRACT FROM AUTHOR]