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Accuracy of pH measurement

Many users ask themselves about the accuracy of pH measurement. There are many influencing variables that are often unknown or not known exactly, even to the expert. What are the main influencing variables, and how can the accuracy be determined?

How accurate is pH measurement – really?

The pH measurement takes place in a measuring system, this consists of the following components:

There are different influencing factors:

  • Interaction pH electrode – measuring medium
  • Accuracy of the pH meter
  • Accuracy of the temperature measurement
  • Accuracy of the buffers used
  • Care taken by the user

A frequent question in pH measurement is “How accurate is the pH electrode?” Interestingly, there are no specifications for it. It provides an mV signal that depends on the calibration and the interaction with the medium being measured, and it is not possible to give an accuracy specification for this.

In principle, the accuracy of the buffers used can never be exceeded whilst measuring pH. This means, for example, when using WTW technical buffers with a deviation of ± 0.03 pH, a measurement can never be more accurate than these limits.

“Tip: As a rule, one must reckon with an absolute accuracy in the laboratory of about 0.1 pH.”

More precise calculations can be found in DIN 19268: Here the user can estimate the influencing variables and then calculate a maximum accuracy for their application.

The all-embracing pH handbook for every application area

pH Handbook SI AnalyticsIn this ultimate pH guide, you will find many application examples, graphs, tables and diagrams, which provide you with everything you need to know about pH from our experts' years of experience, clearly and concisely on 100 pages. Other relevant questions on the pH parameter are also covered in the blog articles:  Download the pH handbook now free of charge as support for your everyday work.

Download pH-handbook

pH-electrode of wtw a xylem brandSupplementary information on pH/Redox can also be found on our parameter page. If you have no more questions, you can easily request a quote for your digital pH electrode from us or order directly via our online store!

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Further questions are answered by our expert in the blog article FAQ pH measurement.

For helpful tips within your application area, you can read our blog articles:

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