Interfacial Properties between N-Decane and Aqueous Solutions of Sodium Cholate, Sodium Deoxycholate and their Mixture

The transfer of sodium cholate (NaC) and sodium deoxycholate (NaDC) from the aqueous phase to the oil phase across the interface, where the single and mixed solutions of two bile salts contact with n-decane, have been studied on the basis of the data of electroconductivity, surface and interface tensions, fluorescence of pyrene and enzymic assay of the bile salts respectively. The break points corresponding to the CMC on each curve (obtained by measuring the surface and colloidal properties of the aqueous solutions after the transfer of the bile salts in contact with n-decane) were found tc shift toward the higher concentrations than those before the transfer as if the CMC were increased. This was explained by checking the transfer of the bile salts using the enzymic assay and by confirming the solubilization of n-decane into the aqueous phase.