Elucidation of Ion Transport Process and Oscillation Processes Through a Bilayr Lipid Membrane and Its Application to Analytical Chemistry.

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The correlation between the voltammogram for ion transfer through a membrane and those at two aqueous/membrane interfaces was elucidated by employing a glass cell with a liquid membrane into which an auxiliary reference electrode was inserted. The membrane transport was found to be controlled by the complementary ion transfers at two aqueous/membrane interfaces. The above methodology and concept were demonstrated to be available to analyze the characteristic reactions of the membrane, like the interdependency between two different charge transfer reactions proceeding at the respective interfaces or the oscillation of membrane potential and membrane current.The ion transport through a bilayr lipid membrane (BLM) was investigated voltammetrically. The ion transport through a BLM was found to be analogous to that through a liquid membrane when the BLM contains sufficient ions, although the BLM is very much thinner than the liquid membrane. It should be stressed that the spontaneous conden … More sation of objective ions from aqueous solution (s) into the BLM by the partition with counter ions is essential for the ion transport through BLMs.Novel oscillations of membrane current or membrane potential were observed when the transfer of Na^+ from one aqueous solution (W1) containing 0.1 M NaCl to another (W2) in the absence of Na^+ through a liquid membrane (LM) containing dilute Na^+ was forced by an applied membrane potential or membrane current, respectively. The current oscillation was induced by the addition of acetylcholine in W1, and inhibited by the addition of such hydrophobic ions as tetraalkylammonium ions or glutamate ion in W1. These oscillations were similar to those at biomembranes with the so-called "sodium channel" as regards both induction and inhibition, though the LM system did not contain any channel proteins. The mechanisms of the oscillations, the induction and the inhibitions were elucidated by referring to voltammograms for the ion transfer through a membrane as well as those at aqueous/membrane interfaces, and by taking into account the adsorption of Na^+ at the LM/W2 interface.In addition, investigations have been carried out for the electron transfer reactions at the aqueous/organic solutions interface, the coupling between the ion and electron transports through a liquid membrane and the quantitative interpretation on the ion-pair extraction equilibrium. Less