How to maintain the probe of a pH meter

How to maintain the probe of a pH meterBy 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.

Nanne Bentvelzen
Questions regarding the pH meter probe

Do you have questions regarding the maintenance of your pH meter’s probe or would you like tailor-made advice? Contact product specialist Nanne Bentvelzen, or fill in the form below. 


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