ROLE OF BRIJ MICELLES IN THE QUENCHING OF FLUORESCENCE OF SAFRANINE-TBY INORGANIC-IONS

The results of quenching of fluorescence of the dye Safranine T (ST) b y the inorganic ions [Fe(CN)(6)](3-), [Fe(CN)(6)](4-), Cu2+, Co2+, Ni2 + and Mn2+ in aqueous micellar solutions of the surfactants diethylene glycol hexadecyl ether (Brij 52), decaethylene glycol hexadecyl ether (Brij 56) and cicosaethylene glycol hexadecyl ether (Brij 58) are pre sented. The quenching results have been processed in the light of Ster n-Volmer (SV) equation and its modified forms to evaluate the extents of interaction between the fluorophore (ST) and the quencher. The magn itudes of the Stern-Volmer constant (K-SV) in quencher micelles follow the trend [Fe(CN)(6)](3-) > [Fe(CN)(6)](4-) > Co2+ > CU2 > Ni2+ > Mn2 + in all the Brij media; for each ion the trend in terms of the surfac tants is Brij 52 > Brij 56 > Brij 58, which is the order of the polari ty of the Bnl environment. The ion Co2+ appears to partly quench the e mission process by the static mode. The solvent parameters of the Brij micellar media like the Kosower Z value, the transition energy for th e intramolecular charge transfer, E-T(30) and the dielectric constant, D, have been estimated from the shift between the absorption and emis sion frequencies. A comparison of the quenching behaviours of inorgani c ions on ST fluorescence in different media viz., aqueous, aqueous po lyethylene glycol and aqueous micellar solutions of Tweens and Brijs h as been presented. (C) 1998 Elsevier Science S.A. All rights reserved.