Dual-State Fluorescent Probe for Ultrafast and Sensitive Detection of Nerve Agent Simulants in Solution and Vapor

The development of fluorescent probes for detecting nerve agents has been the main concern focus of research because of their lethal toxicity for humans. Herein, a probe (PQSP) based on the quinoxalinone unit and the styrene pyridine group was synthesized and could visually detect a sarin simulant diethyl chlorophosphate (DCP) with excellent sensing properties in solution and solid states. Interestingly, PQSP showed an apparent intramolecular charge-transfer process by catalytic protonation after reacting with DCP in methanol, accompanied with the aggregation recombination effect. The sensing process was also verified by nuclear magnetic resonance spectra, scanning electron microscopy, and theoretical calculations. In addition, the papered test strips of loading probe PQSP exhibited an ultrafast response time within 3 s and high sensitivity with a limit of detection of 3 ppb for the detection of DCP vapor. Therefore, this research provides a designed strategy for developing the probes with dual-state emission fluorescence in solution and solid states for detecting DCP sensitively and rapidly, which can be fabricated as chemosensors to visually detect nerve agents in practice.