Application of online ph meter in Ultra-pure Water
Not only the conductive medium in water is almost completely removed, but also the undissociated colloidal substances, gases and organic substances in water are removed to a very low level. The resistivity is greater than 18 mω * cm, or close to the limit value of 18.3 mω * cm.
Because ultrapure water has its unique characteristics, it is very difficult to measure ph value by online ph meter. In practice, it is difficult to obtain repetitive and stable measurement results in samples with low ionic strength. Low ion samples, that is, low alkalinity, low ionic strength, or low conductivity (conductivity is generally 0.056-10) and high impedance, such as deionized water. Because of the changing junction potential in the reference junction, different pH values will be produced when deionized water is measured, even if it is a new, sealed electrode, and it will be well corrected in buffered standard solution.
1. Why do you need online ph meter to measure the pH value of pure water?
In the production process of pure water, measuring pure water can be used as an indicator of process pollution. When air or carbon dioxide invades the pure water production or distribution system, it will lead to pH drift.
2. How to choose online ph meter PH electrode?
The extension bridge electrode is refillable and specially made of low impedance glass. A circulating reference junction has a relatively high circulation rate, which reduces the junction potential. The sealed electrode, usually filled with gel, has a great advantage of long life because of its very slow leakage rate of reference solution. However, the faster leakage rate is very suitable for ultra-pure water because the pH potential can be quickly stabilized.
