1998 Fiscal Year Final Research Report Summary
Preparation of high performance pH-sensors for practical use in nonaqueous solutions
| Project/Area Number |
09554049
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
分離・精製・検出法
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| Research Institution | Shinshu University |
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Principal Investigator |
IZUTSU Kosuke Shinshu University, Faculty of Science, Professor, 理学部, 教授 (70025336)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Akihiko TOA Electronics Ltd., Department of Scientific Instruments, Vice section chairma, 科学計測事業部, 課長代理
ITO Yoshitaka Shindengen Electric Mfg.Co.Ltd., Research and Development Center, Vice chairman, 研究開発センター, センター長付
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| Project Period (FY) |
1997 – 1998
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| Keywords | pH-sensor / pH-ISFET / iridium oxide pH-sensor / nonaqueous solvent / potentiometry / pH standard / titration in nonaqueous solvents |
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| Research Abstract |
The need of pH measurements in nonaqueous solutions is increasing recently, but there is no adequate pH-sensor for use in nonaqueous systems. A glass electrode is the most commonly used pH-sensor, but its response in nonaqueous systems is often very slow. The' aim of the present research is to improve this situation. Two pH-ISFETs (Si_3N_4-type and Ta_3O_5-type) and IrO_2 pH-sensor were employed. I) By improving the sensors, we could make all of the three sensors durable for more than six months in various organic solvents. 2) All of them responded with Nernstian or near-Nernstian slopes to the pH in various nonaqueous and mixed solvents. The response speeds were in the order Si_3N_4-ISFET>Ta_3O_5-ISFET.IrO_2-sensor"*"glass electrode. The response of the Si_3N_4-ISFET was so fast that the rate of mixing the solution ("*"1 s) determined the rate of response. Moreover, the response of the pH-ISFET was not influenced by oxidizing and reducing agents. 3) Almost satisfactory titration curves could be obtained in 10 s with the Si_3N_4-ISFET for acid mixtures, though with a glass electrode, one hour or more was necessary. 4) Various acid-base equilibria were studies by use of pH-ISFETs and their superiority over the glass electrode was proved. 5) The buffer capacity of the pH-standard proposed by IUPAC was tested by use of pH-ISFET and its lack of buffer capacity in aprotic solutions was found. A manual is now under preparation to show how to make the pH measurements in nonaqueous solutions by use of these new pH-sensors.
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Research Products
(10 results)
