What is a dual liquid reference electrode for ph tester ? What are its advantages?
The structure of the double-liquid reference electrode has two liquid junction and two reference solution chambers.
The outer cavity is generally KNO3 solution, the inner cavity is KCl solution, which has two significant advantages: First, to reduce pollution, the test solution can only contaminate the solution in the outer cavity of the cavity KCI solution has little effect; Second, to reduce the clogging of the liquid junction and the chemical reaction between ions, for example, if the measured solution containing S-, I- plasma and reference solution of Ag + reaction, the formation of insoluble silver Compound plugging liquid junction.
A single double-junction reference electrode is commercially available, Model 217 calomel electrode. Double liquid reference electrode is more used for industrial pH electrode.