A ratiometric ionic liquids-based micro-optode for instant and specific detection of nerve agent analog

Designing advanced photofunctional materials within the core of ionic liquids (ILs) has stimulated considerable attention within the scientific communities due to their impactful significance and physicochemical properties such as ionic nature, low melting point, non-volatility, and tunability without hampering their inherent photofunctionality. Herein, we have synthesized a photoluminescent IL, HTIL from 8-hydroxy pyrene-1,3,6-trisulfonic acid trisodium salt [HPTS] and trihexyltetradecylphosphonium chloride ([TTP]Cl) by simple ionic exchange reaction. Water-dispersible IL-based low-dimensional materials referred to as nHTIL were developed by a reprecipitation technique and validated using various spectroscopic and microscopic analyses methods. We have successfully demonstrated that neat HTIL could be used as a solvent-free fluorescent ink and checked its superiority as a security writing tool. A ratiometric cyanish to bluish fluorometric change is observed upon the addition of diethylchlorophosphate (DCP), a sarin mimic in the solution having detection and quantification limits within the µM range. Also, a portable and super handy paper-based test kit experiment has been illustrated and performed verifying DCP detection in the solid phase. A vapor strip-based experiment by nHTIL was conducted to explore the vapor phase detection of DCP. This report presents an innovative way to develop DCP-sensitive IL-based low-dimensional materials exhibiting remarkable properties compared to traditional ones for forensic and environmental monitoring.