A chemodosimetric approach for the visual detection of nerve agent simulant diethyl chlorophosphate (DCP) in liquid and vapour phase

Abstract

In this work, a novel fluorescent ratiometric switch, 8-((6-(1H-benzo[d]imidazol-2-yl)pyridin-2-yl)methoxy)quinoline (BIPQ), has been introduced for sensing an organophosphorus (OP) chemical vapor threat, diethyl chlorophosphate (DCP), the low-toxic mimic of the real nerve agent sarin (GB). BIPQ is efficient at detecting DCP in both solution and gaseous phase and has potential practical application with high sensitivity and selectivity. The probe shows significant ratiometric emission in the presence of DCP along with a distinct color change from blue to cyan under UV light. The sensing mechanism of the chemodosimeter is based on the generation of a new adduct, BIPQ–DCP, through a nucleophilic substitution reaction with DCP followed by a ring-closure process to form the final product. The detection limit of BIPQ for DCP was determined to be in the order of 10⁻⁸ (M) in the liquid state. DFT and TDDFT computational techniques were carried out in order to interpret the electronic properties theoretically.