Rhodamine phenol-based fluorescent probe for the visual detection of GB and its simulant DCP

Abstract

Nerve agents always pose a serious threat to human safety and health as a result of their extremely high toxicity and convenient transport, which has prompted much effort to develop some methods with fast response and high selectivity for detecting nerve agents. Herein, we designed and synthesized two simple rhodamine phenol-based derivatives (RBNP and RBMP). From spectral experiments, we found that RBNP exhibited a significant change of absorption and fluorescence intensity with the nerve agent simulant diethylchlorophosphate (DCP), which could give rise to a fast response within 10 s and high sensitivity with an extremely low detection limit of 1.4 nM in the solution. The sensing mechanism could be attributed to it forming a stable five-membered ring by intramolecular bonding under protonation on the basis of experimental and theoretical calculations. Furthermore, test strips were successfully prepared by immersing TLC plates into the probe RBNP solution and these also achieved a visual system for detecting GB vapor. Therefore, a fast and convenient prospective test method is reported for visually detecting real nerve agents.