Physico-chemical studies on the binding of dyes with surfactants: II. Polarography of surfactant-dye mixtures

Abstract

The polarographic method has been used to determine the binding of the acidic dyes, congo red and alizarin red S, to cationic surfactants (cetylpyridinium bromide—CPB, and cetyltrimethylammonium bromide—CTMAB) and that of the basic dye, methylene blue, to the anionic surfactant, dioctyl sodium sulphosuccinate (Manoxol OT). The surfactant concentration did not affect the combining ratio of dye to surfactant. Similarly, the pH of the reaction mixture had no influence on the combining ratio of dye to surfactant in the case of alizarin red S. A slight positive shift in E1/2 of methylene blue in the presence of Manoxol OT was realized at higher surfactant concentration. The calibration curve of surfactant concentration vs. decrease in wave height was used to determine the concentration of anionic and cationic surfactants.