3D Fluorescence Spectroscopic investigation on the interaction of Alizarin Red dye with Ionic Micelles

Abstract

We have explored the interaction of Alizarin red dye (Sodium salt of 1,2-dihydroxy-9,10-anthraquinone-3-sulfonic acid) with two ionic micelles, Sodiun dodecyl sulphate (SDS) and Cetyl trimethyl ammonium bromide (CTAB) using steady state and three dimensional (3D) fluorescence spectroscopy. Change in the absorption spectral profile of Alizarin red with the two different charged surfactants were measured and is due to the encapsulation of Alizarin red within the micellar microenvironment. Emission intensity is decreased and the wavelength is red shift at higher concentration in presence of SDS anionic micelles. In contrast, the wavelength is blue-shifted in presence of cationic micelle, CTAB indicating the strong interaction between Alizarin red and CTAB. The binding parameters (binding constant and binding sites) are determined from fluorescence emission intensity values using steady-state experiments. Binding of Alizarin red dye with both the ionic micelles occurred via, hydrophobic and electrostatic interaction.