Order Entry

pH Measurement

pH measurements using a pH meter can only be correct and precise when you are using the right buffer for your instrument. Depending on the instrument and your pH measurement range, different buffer solutions and different temperatures can be required. Whatever your requirements are, Avantor® has a pH buffer solution that matches your needs.

pH measurement​ | Avantor

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A large range of buffers that are very accurate and traceable to NIST, DIN 19266 and IUPAC.

Measure the pH range of a solution quickly and easily.

Ideal for exact calibration of your pH meters. Buffers produced by accredited ISO 17034 supplier.

Easily identify your pH solutions to avoid calibration mistakes.

If I order a pH meter, what accessories do I need?

You need a pH electrode and at least two pH buffers, one at pH 7 and the other at pH 4 or 10. Optional accessories that will prolong the life of your electrode include: Storage solution, soaker bottles and cleaning solution.

How do I measure pH?

There are two ways to test for pH:

1. pH strips or indicator paper
2. pH meter and electrodes

Do I need a portable bench meter?

If you want to measure pH in the field and transport the pH meter from place to place, you have to use a battery. If the meter is stationary, as in a lab, choose a bench top version.

How should I store my electrode?

The best solution for storage is 4 M KCl. pH 4 buffer, pH 7 buffer or tap water will also work as a storage solution. Caution: Never store your electrode in distilled water.

How often do I need to calibrate my pH meter?

Our recommendations are that you calibrate each time you use it or each set of uses.

Should I stir my sample during pH measurement?

Yes. There are two main advantages to slowly stirring or gently agitating the sample during a pH measurement. First, the increased flow of the sample across the electrode results in a faster response time. Second, the solution is properly homogenated so no areas of increased or decreased pH exist.

How do I take a pH measurement in soil?

Prepare the sample by combining 5 g of a soil sample with 5 g of distilled water, mixing thoroughly and allowing the mixture to settle for 10 minutes. Carefully insert the probe so the bulb is in the soil and the junction is in the supernatant. Allow the reading to stabilize.

Can I measure the pH of a gas?

The only way to measure the pH of gas is to dissolve it into distilled water and measure the mixture.

Why is accreditation ISO 17034-2016 essential for pH buffers?
  • ISO 17034-2016 for suppliers means that all the buffers are produced and tested by an expert ensuring you can totally rely on the quality of these products.
  • Accreditation is based on the presence of a competent testing lab, where not only qualified staff have to be employed, but where each and every analysis carried out has to correspond to specified criteria.
  • All instrumentation used is regularly checked by officially authorized calibration laboratories.
  • All relevant parameters used in measurement (Weight and T°) correspond to national and international standards.
  • General requirements for the competence and consistent operation of reference material production.
  • All methods that the manufacturer uses to certify their standards must be validated and proven to be accurate.