APPENDIX
A pH meter is a precision measuring device that requires proper use and good
maintenance.
Basic principles of a pH meter:
The basic components of a pH meter are a reference electrode and an indicator electrode. The
reference electrode has a set value and thus provides a fixed reference against the indicator electrode.
The indicator electrode can be easily distinguished from the reference electrode. The indicator
electrode is very often bulb-shaped. In certain other models it can also be a window. This little glass
bulb is very vulnerable and needs to be protected properly against all kinds of influences. May only
come into contact with liquids. Therefore avoid to use fingers, tissues, paper, brushes, etc. The
indicator electrode is positioned in an electrolytic environment.
The disadvantage of the pH meter is that the electrodes are unfortunately not permanent. Many elec-
trodes are spent after only one year. The lifespan is determined not only by the frequency of use but
also by the way in which they are used and maintained.
The better you protect your meter, the longer its longevity
.
A few pointers:
- Rinse the electrode in demineralised water before and after each use. Make certain that no residues
adhere to the electrode.
- Always keep the electrode in some storage solution.
- Never store the electrode in demineralised water.
- If crystals form (after a long storage without use), rinse with demineralised water and let it soak for
one day in storage solution.
- If the measured value appears slowly, this indicates reduced electrode activity.
- If you have a refillable electrode that you wish to refill, first drain the electrode. The electrolyte is no
longer fit for purpose and will always have to be replaced entirely. After refilling, allow the meter to
stabilise for a few hours and then recalibrate.
- A temperature above 50°C is not good for the electrode and reduces its longevity.
- The reason for the repeated recalibrations of a pH meter is the result of the constantly reduced activ-
ity of the electrode.
- Always start calibration with a pH 7 buffer fluid. Follow with pH 4. When changing the buffer fluid,
always rinse thoroughly with demineralised water.
• Calibrate weekly in case of daily use.
• Calibrate monthly in case of weekly use.
• Calibrate each time in case of sporadic use.
• Store the buffer fluids preferably in a refrigerator and allow them to reach room temperature be-
fore use.
- Do not reuse used buffer fluid; this will be contaminated by exposure to air,...
- Never place the electrode directly in the flask with the buffer fluid; it is best to pour a small amount
into a separate, little container.
- Change electrodes:
• if calibration is no longer possible;
• if refilling (if applicable) is no longer possible;
• if cleaning does not help;
• if the electrode is damaged.
Brouwland
Korspelsesteenweg 86 • B-3581 Beverlo - Belgium
Tél. +32 11 40 14 08 • Fax +32 11 34 73 59
[email protected] • www.brouwland.com
Manual
013.113.6 pH meter pHSCAN30
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