Gel Filtration of Mixtures of Surfactants on Sephadex

Abstract

Abstract The gel filtrations of mixtures of sodium dodecyl sulfate (SDS) and sodium tetradecyl sulfate (STS) have been studied for different mole ratios of STS/SDS with varying total concentrations. Above the critical micelle concentration (CMC) of the mixture, two retention volumes V1obs and V2obs were obtained from the elution curve, and the difference between V1obs and V2obs depends on the total concentrations of the mixture. The initial part of the effluent contains only STS, which means that the separation of STS from the mixture occurs after passing through the column. These results have been discussed by taking into consideration the equilibrium between monomers and micelles for the mixtures of the two surfactants. It is shown that the separation factor is determined by the CMC values of the two surfactants—the greater the ratio CMCA/CMCB (CMCA>CMCB), the greater the degree of separation.