How to maintain the probe of a pH meter
By maintaining your
pH meter well you will extend its lifespan and ensure that your measurements are as accurate as possible. The probe’s maintenance is of special importance, because this part does the actual measuring. The probe is a very fragile part which needs to be handled with care. Here are a few tips.
Avoid direct contact
Avoid direct contact with the sensor. This causes damage, which will cause the pH meter to get large discrepancies. If contact is unavoidable, use soft paper to handle the probe (e.g. A
tissue).
Rinsing after use
Rinse the probe well after each use with
demineralized water. This is especially important when measuring aggressive materials or in solutions that contain heavy metals or proteins. This way you will remove residue from the probe which lessens your chances of damage.
Store damp
Store the probe damp. This prevents contamination from drying onto the probe. Place some
additive solution into the protective cap. Never use tap or demineralized water for this, neither are appropriate for this.
Cleaning the pH meter probe
If there is contamination, clean the probe. The product to use depends on the type of contamination.
- Algae growth: use a light soap solution or alcohol. Do not completely immerse the probe, but dip 3-5 cm into the solution and let soak for 15 minutes.
- Fat and oil: use a water soluble organic cleaner, e.g. acetone. Rinse well afterwards with demineralized water.
- Protein: use a HCl/pepsin solution and let the probe soak for a few hours, then rinse well with demineralized water.
Calibrating
If your measurements are not stable you will need to
calibrate your pH meter. You will determine the deviation of the pH meter by comparing values to international standard values, so will know how far out your meter is.
Replacing the electrode
When it is no longer possible to calibrate your meter, the
probe will need to be replaced. Ensure that the pH meter connector makes good contact and that the tester’s pawl matches the slot in the probe. If you don’t do this the meter won’t work properly. After replacing the probe you will need to calibrate the meter.
Questions regarding the pH meter probeDo you have questions regarding the maintenance of your pH meter’s probe or would you like tailor-made advice?
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