Dye exchange in micellar solutions. Quantitative analysis of bulk and single molecule fluorescence titrations

作者:Pineiro Lucas; Freire Sonia; Bordello Jorge; Novo Mercedes; Al Soufi Wajih*
来源:Soft Matter, 2013, 9(45): 10779-10790.
DOI:10.1039/c3sm52092g

摘要

A quantitative empirical model is presented, which relates the total surfactant concentration with the fluorescence intensity and the mean translational diffusion coefficient of dyes in micellar solutions, as determined by Fluorescence Correlation Spectroscopy (FCS). Based on this model a systematic data analysis method is defined for the precise determination of the dye binding equilibrium constant, the critical micelle concentration, the translational diffusion coefficients, and the hydrodynamic radii of dyes and micelles and related properties. The method can be used for the routine and automatic determination of the cmc of surfactant solutions. The model is applied to dyes with very different hydrophobicity in aqueous solutions of the non-ionic surfactant Triton X-100. As a reference the cmc of Triton X-100 is also determined directly from changes in the absorbance of its phenyl-ring applying a ratiometric method.

  • 出版日期2013