Abstract: The invention relates to the use of an organic solvent selected from 2,2,2-trifluoroethanol, ethylene glycol or ethylene glycol dimethyl ether for enhancing formation, potential formation, fluorescence and/or detection of an exciplex. The invention is applicable particularly to nucleic acid hybridisation assay using two polynucleotide probes that will hybridise to a target nucleic acid. Each probe is labelled with one of two partners capable of forming an exciplex such that, on photoirradiation, the exciplex is formed when the probes are hybridised to the target nucleic acid.

Abstract: Compounds capable of forming an intramolecular exciplex on photoirradiation of the compound in water comprise two exciplex forming partners, one being a donor moiety and the other an acceptor moiety, each having at least one aromatic nucleus and being connected by a saturated aliphatic chain having the flexibility to allow said partners to come into exciplex forming relationship. The compounds may be used as labels for oligonucleotides. Certain of the compounds display pH sensitive emission.

Abstract: The present invention relates to a method of detecting nucleic acids and particularly to a method of analyzing for the presence and/or amount of a nucleic acid.