pH Calibration

pH Calibration Tips

Posted on August 8, 2019

Experts at Ohaus have put together a list of tips on pH calibration. Highlights include the following:

  • How often does the pH electrode need to be calibrated?
    • The frequency of electrode calibration is dependent on the precision requirement, sample temperature, surrounding environment and process arrangement of sample test (for example, interference ingredient, flushing and storage, etc.).
    • In order to ensure the accuracy of measurement results, we recommend you calibrate it frequently, preferably one calibration or verification every 10 measurements.
    • If the sample has a complex composition or the electrode is used frequently, you should increase the frequency of calibration.
  • What should be done if the pH calibration slope is higher than 105%?
    • Check the buffer solution’s expiry or whether it has been polluted. If it expired, use a new buffer solution.
    • Check whether you have selected the correct buffer solution.
    • The buffer solution group is set wrong. Select the correct buffer solution group as per the buffer solution used.
  • Why does the result of pH measurement fluctuate for a long time?
    • Generally, it requires 1-4 minutes for the reading of a pH measurement to be stable. If it exceeds a reasonable time, then see the following:
      • The selected pH electrode cannot handle the present sample.
      • Electrode is aged.

The Ohaus Starter 5000 pH Bench Meter offers everything you need for accurate pH measurement.


Manufacturer:   Ohaus

Industries:   Food / Beverage, Plastics

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