title: Study of the formation of dye-induced premicellar aggregates and its application to the determination of quaternary ammonium surfactants.
abstract: Formation of dye-induced mixed premicellar aggregates from binary surfactant solutions is proposed for the determination of alkyltrimethylammonium surfactants at the muM level. The Coomassie Brilliant Blue G (CBBG) dye, negatively charged, induces the formation of cationic surfactant aggregates at concentrations far below the cmc. The role of CBBG in the formation of premicelles was studied by using pyrene as a fluorimetric probe. Formation of CBBG-cationic surfactant aggregates of well-defined stoichiometries that depend on the total surfactant concentration added is demonstrated. Also, the influence of analytical parameters affecting the concentration at which a given aggregate is formed was studied. Linear calibrations for alkyltrimethylammonium surfactants were obtained by using different cationic surfactants as titrants; therefore, the previously derived measurement parameter for mixed micelles is applicable to premicellar aggregates as well.
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, E-14004 Córdoba, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Casero
authors.forename: D
authors.initials: D
authors.lastname: Sicilia
authors.forename: S
authors.initials: S
authors.lastname: Rubio
authors.forename: D
authors.initials: D
authors.lastname: Pérez-Bendito