| 摘要 |
PURPOSE:To achieve a longer life of an electrode and a higher measuring accuracy, by a method wherein a liquid junction surface with a gelatinous internal liquid or a sample solution of a liquid junction member made continuous therefrom is covered with a hydrophilic porous thin film to control a diffusion amount of ions from the gelatinous internal liquid satisfactorily. CONSTITUTION:A liquid junction surface B with a gelatinous internal liquid G or with a sample solution of a liquid junction member E made continuous therefrom is covered with a hydrophilic porous thin film X so as to be kept away from direct contact with the sample solution, which makes the whole of the thin film concerned in the control of ion diffusion amount from the gelatinous internal liquid G. With such an arrangement, a diffusion amount of ions can be maintained constantly for a long period without being controlled by the concentration state of the gelatinous internal liquid G. Once a moisture evaporation preventing agent such as glycerine contained in the gelatinous internal liquid G is introduced into the hydrophilic porous thin film X, the surface of the film always constitutes an ideal liquid junction part without being dried. This setup achieves a longer life of an electrode and a higher measuring accuracy significantly. |
