Look if there is a visible tape around the reference diaphragm or aperture, which might have been placed in factory against drying. Make sure it is completely removed before using the electrode. A pH electrode is active and stable only after wetting! For this purpose, an electrode that has been stored dry must be immersed for at least ten hours in the reference electrolyte solution (3…4 M KCl, article code B520 or B020).
Avoid a low pressure inside a refillable electrode! Therefore always remove the closure from the refilling aperture during the measurements as well as during the calibration. This allows the saltbridge solution to flow through the ceramic liquid junction and prevents contamination of the electrolyte. For the same reason, the inside level should always be higher than the outside level of the measuring solution. Close the refilling aperture again when storing the electrode.
Note: never store your electrode in distilled water!
Proper electrode storage maximises electrode performance and extends electrode life:
For long-term storage information refer to the appropriate pH electrode instruction manual.
The pH electrode wears away by being used. If the electrode tends to respond slower and calibration becomes difficult, even after cleaning, it should be replaced by a new one.
Use the Consort cleaning solution B530 to clean the electrodes for general use. This action is preferably done on a regular time base to ensure a continuous good operation as much as possible.
Depending on the possible contaminants, use the guide below to choose the appropriate solution:
After any of the cleaning procedures, thoroughly rinse the electrode with distilled water, drain and refill the reference chamber, and soak the electrode in storage solution for at least 1 hour.
First check the interior wire. If corrosion is evident, replace the electrode.
To unclog a clogged junction, soak the electrode in pH 4 buffer solution or 3M KCl solution at 60°C for 15 minutes. Allow it to cool in unheated solution and rinse it with distilled water.
Restore a dry electrode by soaking it in tap water after rinsing out the refill chamber with distilled water and refilling with the proper solution.
If neither of these methods restore the electrode to normal condition, replace it.
The performance of a pH glass electrode may become less in time. This can be observed as: slower response, instability and less accuracy. These effects might be improved by maintenance. If maintenance doesn't improve the performance, rejuvenation of the electrode might enlarge its life.
Rejuvenation can be applied using one of the following methods (in order of preference):
* NH4HF2 etches the glass! This will cause the bulb to become thinner and will shorten the life of the electrode.