FLUORESCENCE QUENCHING OF ACRIDINE-ORANGE BY AROMATIC-AMINES IN CATIONIC, ANIONIC AND NONIONIC MICELLES

The fluorescence quenching of acridine orange and its C12 derivative by diphenylamine, 2-naphthylamine and N,N-dimethylaniline in sodium dodecylsulphate (SDS), cetyltrimethylammonium chloride (CTAC) and polyoxyethylene dodecyl ether (Brij-35) micelles was used to determine the binding constants K, for the aromatic amines to the micellar pseudophases. The larger K values observed for the CTAC and Brij-35 systems, compared with SDS, suggest the existence of specific interactions between the quencher and the surfactant as additional contributions to the solubilization process. The behaviour of the relative fluorescence intensity as a function of the average occupation number of the quenchers can be described by a model which assumes that the species are immobile during the lifetime of the probe.