Mercury use in our products About dissolved oxygen (DO) : Dissolved oxygen sensor 【Diaphragm electrode method】
In addition to manual analysis such as iodine titration and mirror modification methods, there are membrane electrode methods using sensors and optical sensor methods for the determination of dissolved oxygen.
【Diaphragm electrode method】
A thin membrane with oxygen (gas) permeability is attached to the electrode tip, and an electrolyte solution and two kinds of metals are placed inside. The membrane is then measured using the redox reaction generated by oxygen and metals. When the working electrode is placed inside the diaphragm as shown in Fig. 2 and the counter electrode is placed inside through the electrolyte, a current proportional to the oxygen concentration transmitted through the diaphragm flows. The type in which a current is measured by applying a constant voltage between both poles is called "polarographic type", and the type in which a current flows without applying a voltage from outside is called "galvanic battery type". Oxygen is reduced and eliminated on the working electrode, so a constant flow rate is required to compensate for oxygen consumed near the septum in order to measure the correct concentration, such as by raising and lowering the submerged stirrer or electrode itself.
