Synthesis and properties of new luminescent acridinium-9-carboxylic acid derivatives and their application in luminescence immunoassays (LIA).

Two new groups of chemiluminescent acridinium labels have been presented: (a) acridinium-9-thiocarboxylates, (b) acridinium-9-(N-sulphonyl)carboxamides. Both groups show higher light yields and faster emission kinetics compared with the known acridinium carboxylate. Owing to the poor storage stability of the thiocarboxylate tracers they are not suitable for commercial use. Acridinium-9-(N-sulphonyl)carboxamides allow a variation of the structure, their stability after conjugation to antibodies is in most cases clearly better than the stability of thiocarboxylate and carboxylate tracers. Light yields and emission kinetics are also superior and good immunoassays have been developed. Therefore, this new class of chemiluminescent labels seems to be suitable for use in commercial assays.