3 ways to extend the life of your pH electrode


3 ways to extend the life of your pH electrode

An ion-selective electrode provides the fastest and most reliable way to monitor and control your pH. However, the measuring technique used for this pH electrode shortens its life, forcing you to replace it frequently. Have you ever thought about why? Or what you can do to improve the replacement interval? Let’s have a look!

1 – Selection

This point, above all others, can ensure the long and happy life of your pH electrode before it goes to the other side. [funeral music] 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.

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

2 – Regeneration

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?

Galaxy pH electrode
Courtesy of NASA

Fun fact: Did you know a pH electrode has more potassium chloride molecules than the number of stars in the Milky Way? Science is so cool!

Okay, back to business! 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.

3 – Rotation

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.


Replacing pH electrodes is inevitable. However, these three tips can make the most out of our electrode friends before they conclude their mission on our planet. You’ll also save money and improve the reliability of your measurements. Try it and see!

Here are some related articles about pH measurement:

How to calibrate a pH sensor: You must calibrate/adjust your pH sensor depending on how accurately you want it to measure. If you need those measurements, then you need this calibration.

6 pH transmitters you must know: Yep, time for another list! We reviewed a couple of pH transmitters last week that you’ll see again in a moment, and we wanted to pop in a few others for you to consider as well. But before we get started, I have a question. Does your accuracy depend on your transmitter? What do you think?

Common errors with pH sensors: Story time! Once upon a time, I had to troubleshoot a pH measurement in effluent water from a wastewater plant. I knew the technicians had properly installed the loop, consisting of pH electrode, cable, and transmitter. A top-down mounted holder fixed the electrode to the side of the outlet channel. Only the sensor came in contact with the water; the cable and contacts stayed safe inside the holder. But they asked me to find out why the plant manager called the measurements “time dependent.”

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