| 摘要 |
PURPOSE:To measure ion activity at a high accuracy by a method wherein a solution to be inspected is spotted on an ion selective electrode and an impedance lowering means is provided near a probe for detecting potential difference of the solution to be switched a potential difference signal for connection. CONSTITUTION:A reference solution is spotted on the side A at one end of ion selective electrodes 3.1A and 3.1B, 3.2A and 3.2B and 3.3A and 3.3B while a solution to be inspected on the side B at the other end thereof and connected in a bridge. Pairs of probes 11A and 11B, 12A and 12B and 13A and 13B are brought into contact with the reference solution and the solution being inspected separately on both sides of these electrodes and potential difference is detected between both the solutions. A circuit board 15 as impedance lowering means is provided near the probes 11A-13B while signals from the probes 11A-13B are switched and connected to the circuit board 15. In this manner, Na, K and Cl ions are measured selectively with the electrodes 3.1A-3.3B, for instance. Thus, as the probes are connected to the circuit board 15 by a switching, the potential difference can be amplified with limited noise thereby enabling the measuring of ion activity at a high accuracy. |
