METHOD OF DETECTION

A method for detection of a nerve agent in a sample, which method comprises (a) irradiating an optical sensing element, the optical sensing element comprising a fluorescent sensing compound provided on a substrate, and measuring the luminescence of the optical sensing element; wherein the fluorescent sensing compound comprises a combination of at least one electron acceptor moiety and, optionally, one or more electron donor moieties such that the electronic properties of the sensing compound are sufficient to enable a change in the luminescence of the sensing element in the presence of the nerve agent, and a moiety that influences solubility of the sensing compound in a solvent; (b) contacting the sample with the optical sensing element; (c) measuring the luminescence of the optical sensing element; and (d) determining whether the nerve agent is present in the sample based on the measurements obtained in steps (a) and (c).