TETRAPHENYLBORATE CONDUCTANCE THROUGH LIPID BILAYER MEMBRANES

At low concentrations of the anion in the water solutions on either side of the membrane (< 0.3 mM), the membrane permeability is so great that transport is limited primarily by diffusion in the water. At higher concentrations the anion flux is independent of concentration; evidently there is an upper limit to the number of anions which can enter the membrane. Recognizing space charge as the probable cause of the latter phenomenon enables one to estimate the mebrane-water partition coefficient (approx. 1) and the anion diffusion constant within the membrane (approx. 10-9 cm2/sec). © 1969.