| 摘要 |
PROBLEM TO BE SOLVED: To improve the measuring accuracy by suppressing the influence of drift due to various factors of detection voltage in a pH sensor using a pH-IS (ion sensitive) FET. SOLUTION: A pH-IS FET 5 for measurement is attached in a thin tube 1 in a manner that its detection part may be exposed from the tip end thereof, and a liquid holding part 4 is provided to the tip end of the thin tube in order to keep a pH buffer communicating with the pH-ISFET 5, then a pH-ISFET 6 for reference and a pusedo comparison electrode 7 are fitted to the liquid holding part 4. To detect a difference between the detection voltage of the pH-ISFET 5 against the electrode 7 and that of the pH-ISFET 6, lead wires 5a, 6a and 7a are led from the pH-ISFETs 5 and 6 and the electrode 7 respectively to the outside of the tube 1. |
