Bi-ionic potentials of bovine lens capsules and collodion membranes

Abstract

Concentration dependencies of bi-ionic potentials of well-cleaned bovine lens capsules in vitro, of collodion and of modified collodion membranes were studied. The lens capsules have positively fixed charges, and collodion membranes have negatively fixed charges. As these membranes are partially selectively permeable, both co-ions and counter-ions exist in the membrane. However, many studies of bi-ionic potentials have been limited to systems in which the membrane has extreme ionic selectvity and co-ions are completely excluded from the membrane. Experimental results agreed with theoretical values obtained by assuming the common ion concentration to be constant throughout the membrane for systems such as KCl(C)-membrane ( θo, or θ<o)-NaCl(C), NaNo 3(C)-membrane ( θo)-NaCl(C) and CaCl 2(C 1)-membrane ( θo)-NaCl(C 2) (C 2/C 1 = 2), where C is the bulk concentration. The theoretical reliability of this assumption was checked. When both electrolytes in solution were uni-univalent, the ratio of ionic mobilities of two counter-ions (or two co-ions) in all of these membranes was almost the same as the ratio obtained in bulk solution, while the ratio of ionic mobilities of the counter-ion and the co-ion was almost the same as the ratio obtained in bulk solution for the lens capsule, but different in the case of the collodion and modified collodion membranes.