| 摘要 |
PURPOSE:To measure the activity of ion in a solution accurately 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 the potential difference thereof to be grounded together with the solution. CONSTITUTION:A reference liquid is spotted on the side A of 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 they are connected in a bridge. Pairs of probes 11A and 11B, 12A and 12B and 13A and 13B are brought into contact with the refrence solution and the solution to be inspected separately on both sides of the respective electrodes and detect the potential difference between the reference solution and the solution being inspected. A circuit board 15 as impedance lowering means is provided near the probes 11A- 13B while an earth 16A is provided between the circuit board 15 and the solutions. In this manner, Na, K and Cl ions are measured selectively, for example, with the electrodes 3.1A-3.3B. Thus, as the impedance lowering means is provided near the probes while being grounded together with the solution, the potential difference is amplified with limited noise to allow a highly accurate measurement of ion activity. |
