PHOTOCHEMISTRY IN MICROEMULSIONS - FLUORESCENCE QUENCHING OF NAPHTHOLS BY SOME GAMMA-PICOLINIUM SALTS

The fluorescence quenching behaviour of naphthols by some water-solubl e quenchers like (methylene)(n) bis-(gamma-picolinium bromide) and 1-h exyl gamma-picolinium bromide have been studied in aqueous medium, and in bath water-rich and oil-rich regions of NaLS (sodium lauryl sulfat e)-isobutanol-hexane-water and CTAB (cetyltrimethyl ammonium bromide)- isobutanol-hexane-water microemulsion systems. From the fluorescence q uenching behaviour, the localization sites of the fluorescent probes i n microemulsions have been identified. The charge on the surfactant he ad group has been found to have significant effect on the quenching ph enomena of the naphthols by the pyridinium salts. Both linearity and d eviation from linearity in Stern-Volmer plots have been observed durin g the quenching process and a sphere of action model has been proposed for positive deviation. (C) 1998 Elsevier Science S.A.