INVESTIGADORES
BERTOLOTTI Sonia Graciela
artículos
Título:
Photophysics of the phenoxazine dyes resazurin and resorufin in direct and reverse micelles
Autor/es:
GABRIELA V. PORCAL, CARLOS M. PREVITALI AND SONIA G. BERTOLOTTI
Revista:
DYES AND PIGMENTS
Editorial:
Elsevier
Referencias:
Año: 2009 vol. 80 p. 206 - 210
ISSN:
0143-7208
Resumen:
The photophysics of the phenoxazin-3-one dyes resazurin and resorufin was studied in a micellar
solution of cetyltrimethylammonium chloride and in reverse micelles of 1,4-bis(2-ethylhexyl)
sulfosuccinate and benzylhexadecyldimethylammonium chloride. Absorption and fluorescence
emission spectra, as well as fluorescence lifetimes and TT transient absorption spectra were determined
as a function of surfactant concentration. In the presence of direct micelles of cetyltrimethylammonium
chloride, both dyes displayed red shifts in the absorption and fluorescence spectra together with a simultaneous
fluorescence lifetime increase. The electrostatic attraction between the anionic dyes and the
positive micellar interface favors the location of the dyes closer to the head groups of the surfactant
molecules. In reverse micellar systems the spectral properties depended upon the charge of the surfactant
and water content. In the case of 1,4-bis(2-ethylhexyl)sulfosuccinate, at low water content both
dyes were incorporated into the interface; as the water content increased their spectral properties
tended to those in pure water. In contrast, in the case of cationic surfactant, the dyes were located in the
interfacial pseudophase as a result of electrostatic interactions.