| 摘要 |
The reference electrode includes a liquid junction portion where an internal solution is brought into contact with a sample solution by a thin film member formed of a substance having a low solubility in water and aqueous solutions and mounted on the liquid junction portion so that leakage of the internal solution to a side of the sample solution can be almost completely prevented. The thin film member forming the liquid junction portion is made of MgF2 or CaF2. A limiting equivalent ionic conductivity of a cation and that of a anion, which are comparatively large, and a transfer coefficient of the cation and that of the anion are nearly equal to each other so that a low solubility in water and aqueous solution can be realized to the extent that it is almost the same if the internal solution was brought into direct contact with the sample solution. In addition, an inter-liquid differential potential can be reduced and stabilized and high accuracy of measurement and reliability can thus be secured.
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