EMPLOYMENT OF A USEFUL LIQUID MEMBRANE-ELECTRODE SYSTEM TO CHARACTERIZE THE MICELLES OF BILE-SALTS AND OTHER DETERGENTS IN PURE AND MIXED STATES

Ion-pairs or coacervates (formed by the reaction between cationic and anionic surfactants) dissolved in nitrobenzene can behave as surfactan t-ion registering devices to respond to both surfactant cation and ani on. The complexes of cetyltrimethyl ammonium bromide with sodium dodec yl sulfate, sodium salts of deoxycholic and chenodeoxycholic acids, an d Aerosol Orange T have been used in nitrobenzene to generate such use ful liquid membranes. The complex of dimethyldioctadecyl ammonium brom ide and sodium cholate has been used to study the cholate ion behaviou r since its complex with cetyltrimethyl ammonium bromide is water solu ble. The electrochemical behaviours of the liquid membranes have been found to be fairly good and reproducible. The membrane potential measu rements have been used to determine the critical micelle concentration s of the surfactants in pure as well as in mixed states to evaluate su rfactant - surfactant interaction in the micelles of the latter.