Fluorescent Sensors for Organophosphorus Nerve Agent Mimics

Abstract

We present a small molecule sensor that provides an optical response to the presence of an organophosphorus (OP)-containing nerve agent mimic. The design contains three key features: a primary alcohol, a tertiary amine in close proximity to the alcohol, and a fluorescent group used as the optical readout. In the sensor's rest state, the lone pair of electrons of the basic amine quenches the fluorescence of the nearby fluorophore through photoinduced electron transfer (PET). Exposure to an OP nerve agent mimic triggers phosphorylation of the primary alcohol followed rapidly by an intramolecular substitution reaction as the amine displaces the created phosphate. The quaternized ammonium salt produced by this cyclization reaction no longer possesses a lone pair of electrons, and a fluorescence readout is observed as the nonradiative PET quenching pathway of the fluorophore is shut down.

Organophosphorous Compounds-Toxicity and Detection Approach

“…Exposure to an OP nerve agent mimic triggers phosphorylation of the primary alcohol followed rapidly by an intramolecular substitution reaction as the amine displaces the created phosphate. The quaternized ammonium salt produced by this cyclization reaction no longer possesses a lone pair of electrons, and fluorescence readout is observed as the nonradiative PET quenching pathway of the fluorophore is shut down (Dale et al, 2006). Anandakathir et al reported the synthesis of stilbene-based fluorophore, 3,4-dihydroxy-4'-aminostilbene (DHAS) for the detection of chemical warfare agents such as organophosphorus nerve gases.…”

Imprinted Polymer Inclusion Membrane Based Potentiometric Sensor for Determination and Quantification of Diethyl Chlorophosphate in Natural Waters

“…There have been many innovations for the detection of this species including colorimetric detection methods [7,8] surface acoustic wave devices [9,10], enzymatic assays [11], interferometry [12] and fluorescent sensors [13][14][15]. However, all are plagued by at least one limitation or other such as slow response, lack of selectivity, poor sensitivity, operational complexities or non-portability.…”

Decontamination of Chemical Warfare Agents

“…It is based on a surfactant system to solubilise sparingly soluble CWA and to increase rates of reaction with nucleophilic reagents. Swager 24 developed a sensitive, fluorescent chemosensor for the detection of nerve agents [22][23][24] . He showed that upon intramolecular cyclisation reaction of nerve agents, he could transform a flexible chromophore into a rigid delocalised system causing offon response in the micromolar concentration range.…”