An ion-selective electrode provides the fastest and most reliable way to monitor and control your pH meter’s electrode (the part in contact with the measured solution). However, the measuring technique used for this pH electrode shortens its life, forcing you to replace it frequently.

 To know more about pH meters and measurement, take a look at our definitive guide here.

I. Selecting the right pH electrode

This point, above all others, can ensure the long and happy life of your pH electrode before it goes to the other side. Choosing the right model requires process data such as measurement range, temperature, and medium composition. Even intermittent stress factors, like chemical cleaning and sterilization, may factor into your choice of membrane and diaphragm.

pH Electrode

Picking the wrong electrode can result in diaphragm clogs, membrane degradation, medium instability, and more.

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Liquiline CM442 Expandable multiparameter field device for all industries
in the shop from 1190 €
CM442

II. Regenerating the pH electrode

Can you extend the life of a pH electrode already in use? Yes! Consider this question: Why does a drop of ink in water spread itself completely through the water?

Ink diffusion pH electrode
Courtesy of Flow Illustrator

We call this phenomenon diffusion. The ink molecules move from the most concentrated point, where the drop fell, to regions of lower concentration, the rest of the water, until it’s uniformly distributed.

Electrodes undergo diffusion too. Instead of ink molecules moving around, an electrode has potassium chloride moving out and contamination moving in. That also explains why some electrodes change color over time. Interesting, isn’t it?

Next, how do you regenerate your electrode? By reversing the diffusion process! Set your electrode in a solution of potassium chloride (3 moles per liter). Some of the mineral salts lost during operation will return and some of the contaminants will leave.

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Orbisint CPS12D Digital glass electrode redox sensor (ORP) for water treatment applications
in the shop from 370 €
CPS12D

III.  Rotating pH electrodes

Another excellent way to prolong the life of your pH electrode is a rotation policy of two or more electrodes. Put one in use and the other(s) in a regeneration solution at the lab. When the time comes to replace the spent electrode, put it into the regeneration solution and install a regenerated electrode to continue your process.

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Ceraliquid CPS41D Digital pH sensor for the chemical and life sciences industry
in the shop from 490 €
CPS41D

to know more pH electrodes and buffer solutions, you can get in touch with our engineers!

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