Difference between rechargeable and non rechargeable pH comp

Difference between rechargeable and non rechargeable pH composite electrodes

 

Core tip: pH composite electrodes can be divided into rechargeable (rehydration) and non rechargeable (gel). There is a liquid adding hole on the shell of the rechargeable pH composite electrode. When the external reference solution of the electrode is lost, the liquid adding hole can be opened and KC1 solution can be replenished。

PH composite electrodes can be classified as rechargeable (rehydration) and non rechargeable (gel). When the external reference solution of the electrode is lost, the hole can be opened to replenish KC1 solution. Instead of the rechargeable pH composite electrode, gel KC1 is not easy to drain and no liquid hole is added。

 

The electrode that has response to the activity of hydrogen ion in solution and the electrode potential changes with it is called pH indicating electrode or pH measuring electrode. The pH indicating electrodes include hydrogen electrode, antimony electrode and glass electrode, but the most commonly used one is glass electrode. The glass electrode is composed of a glass rod and a glass membrane which is sensitive to hydrogen ions. The glass film is generally spherical, filled with internal reference solution, inserted into the internal reference electrode (silver / silver chloride electrode in general), sealed with electrode cap, and installed with socket to form a pH indicator electrode. A single pH indicating electrode can not be measured, it must be measured together with the reference electrode。

 

The electrode with known and constant electrode potential, which has no response to hydrogen ion activity in solution, is called reference electrode. The reference electrodes include mercurous sulfate electrode, calomel electrode and silver / silver chloride electrode. The most commonly used electrodes are calomel and silver / silver chloride. The pH composite electrode is composed of pH glass electrode, reference electrode and temperature compensation electrode. The biggest advantage of composite electrode is easy to install, calibrate and use. The pH composite electrode is mainly composed of glass electrode (composed of electrode bulb, glass support rod, etc.), external reference electrode, external reference solution, temperature compensation electrode, liquid junction, electrode cap, electrode wire, etc。

 

The characteristics of the rechargeable pH composite electrode are that the reference solution has a high penetration rate, the liquid interface potential is stable and reproducible, and the measurement accuracy is high. Moreover, KCl solution can be added or replaced when the reference electrode is reduced or contaminated, but the disadvantage is that it is inconvenient to use. When using the rechargeable pH composite electrode, the filling hole should be opened to increase the liquid pressure and accelerate the electrode response. When the electrolyte level is low, new electrolyte should be added in time。

 

Non rechargeable pH composite electrode is characterized by simple maintenance and easy use, so it has been widely used. However, when used as pH electrode in laboratory, the concentration of KCl at liquid junction will decrease under long-term and continuous use conditions, which will affect the test accuracy. Therefore, when the non rechargeable pH composite electrode is not in use, it should be immersed in the immersion solution of the electrode, so that the performance of the electrode will be very good in the next test, and most of the pH electrodes in the laboratory are not tested for a long time and continuously, so the effect of this structure on the accuracy is relatively small。

 

The most familiar and oldest zero current measurement method used to determine the chemical reaction process is probably pH measurement. Generally speaking, pH measurement is used to determine the pH of a solution。