1990 Fiscal Year Final Research Report Summary
Foundamental Study on Development of Ion-selective Electrodes of Anion Carrier Type
| Project/Area Number |
01550580
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業分析化学
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| Research Institution | Kumamoto University |
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Principal Investigator |
JYO Akinori Kumamoto University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40038047)
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| Co-Investigator(Kenkyū-buntansha) |
KOIDE Yoshifumi Kumamoto University, Faculty of Engineering, Lecturer, 工学部, 講師 (40040430)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Anion carrier / Ion-selective electrode / Macrocyclic polyamine / Liquid membrane / Membrane potential |
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| Research Abstract |
Anion carriers, which can enhance extractability of some anions into water immiscible organic solvents through specific interaction or complexation with them, are expected to play important roles not only in the field of analytical but also in understanding of in vivo anion transport phenomena. In this work, we have studied physio-chemical properties of some anion carriers in order to obtain anion carrier based ion-selective electrodes with high performances. The following directional and satisfactory results were obtained.
(1) Strong association between the carrier and anions reduces net charge density in a membrane resulting in extremely high impedance of the membrane. Thus, background response of the membrane matrix will give a significant influence on overall response of the electrode. In this work, we have resolved this problem by adding a hydrophobic ion pair to the membrane to enhance its conductivity. As long as the ion pair does not interact with the carrier, membrane potentials can be successfully measured without loss in the property of the carrier.
(2) By means of physiochemical approaches, such as X-ray crystallography, conductivity measurements and examination of partition equilibria, properties of complexes of cobalt (III) or molybdenum (V) with macrocyclic tetraaza ligands as an anion carrier have been investigated. It turned out that sp^2 nitrogen atoms should be needed for rapid and specific interaction between the central metals of the complexes and the anions.
(3) Complexing ability of a carrier with anions cannot be straightforwardly correlated to potentiometric selectivity but it is more closely related to selectivity in solvent extraction.
(4) Theory on potentials across a liquid membrane containing an anion carrier has been proposed. The theory gives semiquantitative explanations for discrepancy between potentiometric selectivity and selectivity in solvent extraction.
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