| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1987: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1986: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
As a part of the study on the applications of ion-selective electrodes in nonaqueous solutions, anion-sensitive glass electrodes were developed and their applicability in aprotic solvents was investigated. Various kinds of glass, goth electronic conductive and ionic conductive and containing Ag_2O and P_2O_5 or B_2O_3, were prepared and membrance electrodes were constructed with them. An electrode of electronic conductive glass with a composition of 5Ag_2O-50P_2O_5- 40MgO-5Al_2O_3 responded in acetonitrile with Nernstian slopes to halide ions and with sub-Nernstian slopes to nitrate and perchlorate ions. The detailed conditions and the reason for the response of the electrode, however, could not be elucidated. The electrode did not respond to the variation of ionic solvation energies. A membrane electrode of ionic conductive glass with a composition of 50AgI-2kAg_2O-25B_2O_3 responded with Nernstian slopes to the chloride ion in various solvents. It also responded almost thermodynamically to the variation of chloride ion solvations. To bromide and iodide ions, the electrode responded with super-Nernstian slopes, both to the concentration variation and to the variation in ionic solvations. We applied the electrode as a sensor of chloride ion solvation and studied in acetonitrile the complexing of chloride ion with water. Successive complex formation constans were obtained. Though the electrode was applicable in aprotic solvents, it was gradually deteriorated in aqueous and alcoholic solutions by the formation of a surface film, probably due to the reaction between Ag_2O in the glass and a halide ion in solution. In order to eliminate this defect, studies on chalcogenide glass membrane electrodes are now in progress. In connection with the study of ionic solvations, the problem of the liquid junction podential between different solvents was also studied in detail.
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