Diffusion interaction of some biologically important compounds with an anionic surfactant sodium dodecyl sulfate in aqueous solution: A conductometric study

The effect of some biologically important compounds such as calcium chloride,calcium fluoride,calcium oxalate,and calcium acetate as well as some α-amino acids on the micellar properties of an anionic surfactant,sodium dodecyl sulfate (sds) was studied by conductance measurement technique. the micellar properties such as the critical micellar concentration (cmc),degree of counterion dissociation (α),degree of counterion binding (f),binding constant (kb) were obtained in this study. it was found that the values of cmc decrease following the order: calcium oxalate < calcium fluoride < calcium chloride < calcium acetate. the cmc values decreased exponentially for glycine and l-alanine which differ for l-valine. the interaction of cholesterol with sds was also studied at different temperatures ranging from 20 to 35°c and the thermodynamic parameters of micellization δgom,δhom and δsom were evaluated according to pseudo-phase model. the values of δgom (negative) and δsom (positive) revealed that the micellzation process is entropy driven and the interaction is hydrophobic.