A room temperature ionic liquid-based molecular chameleon for selective and sensitive detection of sarin analog

To ensure the safety of our globe from the deadly nerve gases used by anti-nationalists, the identification and quantification of these lethal substances require more attention from the scientific community. The present report introduces an anionic ionic liquids (ILs)-based chromogenic probe CsIL, which is prepared based on an ion exchange reaction between sodium salt of 4-amino-1-naphthalenesulfonic acid and the ionic liquid trihexyltetradecylphosphonium chloride (TTP⁺Cl⁻) and the resultant, followed by simple condensation with N, N-dimethyl cinnamaldehyde, which instantly detects the deadly nerve agent sarin gas mimic diethylchlorophosphate (DCP) in both liquid and gas phases. This ILs-based model probe CsIL exhibits remarkable sensitivity and selectivity towards DCP with detection and quantification limits of 11.3 nM and 37.6 nM, respectively, as well as a binding affinity constant of 14,847.9 M⁻¹, thus surpassing many existing chemosensors and being found to be more advantageous than non-ILs-based ones. The probe CsIL instantly identifies DCP specifically and selectively by showing a visual colorimetric change from yellow to pink, which is reversed in the presence of triethylamine (TEA). Also, to ensure a real-time handy application, a paper-strip based test kit experiment is been performed for the convenient and reliable detection aid to detect DCP. To explore more about the probe, a smartphone-based experiment is also performed, which provides an outstanding route for the on-site visual detection and quantification of DCP in the presence of different analytes. Furthermore, real sample analysis is also performed by collecting and testing different types of soil to prove the applicability of our probe CsIL in real applications. Therefore, our model CsIL may prove to be a reliable and effective candidate for the detection of DCP, ensuring the ability to detect sarin gas in real threat scenarios.