| 摘要 |
A pH sensor includes a unitary cylindrical semi-porous plug which is formed with a central bore and is also formed with a cavity near a first end of the plug. A pH electrode is positioned in the central bore and extends outwardly from the second end of the plug for contacting a specimen fluid, and a reference electrode is positioned in the cavity. The plug is saturated with an electrolyte to establish electrochemical conductivity between the reference electrode and specimen fluid. To prevent ions from the specimen fluid from migrating through the plug and contaminating the reference electrode, a plurality of notches are radially machined part way through the plug and filled with ionimpermeable epoxy. The notches are preferably oriented at oblique angles relative to the axis of the plug to form "dead end" ion traps that will immobilize and impede a substantial proportion of contaminating ions, thus prolonging the life of the electrode.
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