A phthalimide-based turn on fluorosensor for selective and rapid detection of G-series nerve agent’s mimics

Abstract

Organophosphorus-based nerve agents are extremely toxic. Their use in terrorist attacks and wars has caused increased interest in developing simple, portable, displayable, and authentic methods for detecting these lethal substances. In this article, we have designed and synthesized a fluorosenor (HBAI) derived from 4-aminophthalimide moiety that exhibits high selectivity and sensitivity towards G-series nerve agent mimics in their solution and gas phases, respectively. HBAI shows significant fluorescence response to DCP and DCNP that induced noticeable bare eye color changes under a 365 nm UV light irradiation. The detection limit of HBAI for DCP and DCNP has been established in the order of 10-7 M and 10-6 M, respectively. The sensing mechanism for the probe HBAI has been elucidated by time-resolved photoluminescence decay analysis and 1H NMR titration experiment. The significant photoluminescence enhancement is mainly found for disrupting the excited state intramolecular proton transfer (ESIPT) mechanism because of the phosphorylation process. However, for the practical utility of HBAI, a test kit employing Whatman-41 filter paper has been fabricated as a portable and displayable photonic device for on-site detection of G-series nerve agents. Also, a dip-stick method has been demonstrated to identify the vapor of G-series nerve agents mimic.