How to Use & Maintain a PH Electrode?
A pH electrode is a part of the pH meter contacting with a measured substance, it's usually used to measure the electrode potential. The service life of the pH electrode starts from the factory, regardless of whether it is used or not, the maximum service life is only 1 year, if the use and management methods are not in place, the service life will be shortened exponentially. This blog will tell you how to use, maintain, and storage pH electrodes.
How to use a pH electrode?
- The pH electrode is often soaked in the test liquid in the process of use, it is strictly forbidden to be dry exposed in the air for a long time, and the dry exposure time in the air should not exceed half an hour in general.
- When the pH electrode is not used temporarily, the electrode should be cleaned with the correct cleaning method and then put in standard buffer solution, temporarily stored in PH=4 buffer solution (such as hydrochloric acid), long-term storage in PH=7 buffer solution (such as saturated potassium chloride solution).
- The electrode is forbidden to be used in high temperature or dry environment, high temperature or dry environment will easily make the surface of the electrode scale, thus the electrode is damaged.
- It is forbidden to use or keep the electrode in the environment close to the freezing point, the freezing point environment is easy to make the electrode cold burst. Under the ambient temperature of less than 15℃, it is normal to use a pH meter to reduce the sensitivity and accuracy of poison.
- The electrode should not be used and stored in an environment with violent vibrations. Otherwise, the electrode may be damaged.
- The electrode is generally cleaned and maintained once a month (ideally every day or every other day) by electrician professionals depending on the situation, the specific time interval depends on the harshness of the test environment, the harsher the environment, the more frequent the cleaning and maintenance (such as solutions containing heavy metals or organic substances, more frequent cleaning and maintenance are required).
- The electrode should be at a height that can truly reflect the PH value of the liquid, generally in the measured liquid below about 200 to 300mm for the appropriate (front glass bulb needs to be completely submerged in the measured liquid).
- The electrode used for the first time or disused for a long time must be soaked in 3mol/L potassium chloride solution for 24 hours for activation before use.
- PH correction, in the actual test normal unavoidable error, can be corrected PH, instrument parameter settings, there is online calibration, select after the PH correction option, and then confirm the correction PH value, according to the actual pH correction, more reduce plus principle, correction range in ± 1 (can send back to re-modify the open correction range).
Daily maintenance of pH electrodes
- General contamination: clean the electrode with water, 0.1 mol/l NaOH or 0.1 mol/l HCl for a few minutes.
- Grease or organic contamination: clean the electrode with acetone or ethanol for a few seconds.
- Sulfide contamination (septum blackening): use a cleaning solution.
- Protein contamination (diaphragm yellowing): use a cleaning solution.
- Regeneration of electrode: treated with regeneration solution. Regeneration can only extend the life of the electrode to a limited extent.
- Sheath pressure maintenance: For ATO pH glass electrodes that need to be pressurized, you should pay attention to the pressure gauge reading on the sheath when using them. In principle, the pressure inside the sheath should be more than 1.5Bar higher than the pressure inside the reactor.
Storage of pH electrodes
- Electrodes should be stored in a suitable liquid when not in use for a longer period of time according to the instructions.
- The electrodes should not be stored dry for a long time and should not be stored with dry media attached to the surface. The dry electrode should be put in the suitable storage solution first before use.
- Electrodes should not be stored in distilled water.