How to maintain a pH meter
pH meters are among one of the most popular scientific devices. They are used everywhere, from laboratories to fieldwork. Easy to use, they provide a wealth of information at the touch of a button. Yet a lot of pH meter users unstate the importance of maintaining their meter, which, if not performed, will result in imprecise or unreliable results and shorten the life of your meter. Thankfully, these problems are easy to avoid.
In this article, Instrument Choice scientists share four maintenance steps that will ensure the ongoing performance of your meter.
About pH Meters
pH meters are designed to measure the acidity or alkalinity of a substance. There is a meter to measure anything from chemicals in a laboratory to soil out in the field, and there is a meter type to suit specific tasks. Models can include, convenient pen meters and handheld devices, right up to professional benchtop meters. No matter the design or use, your pH meter will occasionally need a little tender loving care and maintenance.
Why and How to Maintain a pH Meter
Just like your car, maintenance of a pH meter is essential to keep it in good working shape, and as a bonus, this will generally prolong the life of your device.
1.Calibration
Regular calibration of your pH meter is essential. The frequency will be determined based on how often you use your device. You can calibrate most pH meters in house, some meters will tell you when they require calibration, and others will not.
If you use your meter every day, you should calibrate it daily. If you use it a few times a week, weekly calibration would likely be suitable. For best results, calibrate your meter to a minimum of two points before each use.
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IC Tip: In addition to calibrating to two points, we recommend that you calibrate to two buffers that shoulder your expected sample, this will be neutral pH seven and the second buffer. For example, if your sample is expected to be pH 5.2, you would use pH 7 and pH 4 as your calibration buffers. |
Watch the Instrument Choice Scientists calibrate a pH meter in the video below.
2.Cleaning
Keeping your electrode clean is an easy way to extend its life. Between measurements rinse the electrode with distilled or deionised water.
A more thorough cleaning will be needed if a coating has started to form over the glass bulb or if the device is performing inconsistently. To do so, place in an electrode cleaning solution for 10-15 minutes then rinse thoroughly with distilled water. Most meters recommend that you do not wipe them down with tissue or cloth, as this can cause static, which could harm the electrode. Check your user manual for device specifics.
After rinsing the electrode, place the device back into its cap with storage solution. It’s best practice to let it sit in storage solution for a couple of hours after cleaning.
Watch the Instrument Choice Scientists clean a pH meter in the video below.
3.Storage
Most pH meters require the electrode to remain in storage solution when not in use. Why? To keep the bulb of the meter at optimum sensitivity. Sensitivity is affected due to the design as pH electrodes have a hydrated gel layer. This layer facilitates the electrical signal needed to obtain a pH reading. Storing a pH electrode dry will seriously reduce its sensitivity.
If you forget to cap your meter once or twice, it may not be the end of the world (we’ve all been there). The remedy is to soak it in storage solution for a couple of hours and perform a calibration to ensure it is working correctly before use.
To be sure, check your electrode’s user manual or operational instructions for specific storage medium details.
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IC Tip: Never, ever, ever, ever store your electrode in distilled or deionised water. If you run out of storage solution, you can substitute with pH 4 in the short term. |
4.Electrode Replacement
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IC Tip: Look for a pH meter with a replaceable electrode. Although more costly outright, replacing an electrode is cheaper than replacing the whole device. |
Unfortunately, not all pH meter users know this, but a pH electrode is generally a consumable item. Depending on use, we recommend you replace your device’s electrode every 6-24 months. Following the three tips above will reduce the frequency of electrode replacement, but when the time comes there are three main things to look out for which will indicate it may be time to replace an electrode;
1.Difficulty or inability to calibrate the pH meter
2.Unstable, variable or slow readings; and/or
3.Physical signs of damage or wear and tear.
If you need any information on whether or not your pH meters electrode is replaceable, or need a replacement and aren’t sure where to find it, contact us.
Watch an example of the Instrument Choice Scientists changing a pH meter electrode in the video below.
Conclusion.
Following the four tips above is the sure way to keep your electrode in shipshape. While maintenance can seem tedious, it will likely save you time and money in the long run.
You can view our range oh pH buffers, cleaning solutions, and storage solutions here.
If you need more information on any of the above steps or need a hand with your pH meter, contact one of the Instrument Choice Scientists, being helpful is what we do!
Call 1300 737 871 or email [email protected].
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