There are so many different types of pH electrodes that it can be hard to select one that will be just right for your application. You may be measuring the pH of water in in a dam, the pH of salad dressing or even cheese…
An electrode has a life similar to that of a battery and usually needs to be replaced every 6 months – 2 years. Electrodes from various manufacturers will fit with most pH meters (a BNC connection is the most common).
Ask yourself these questions, or let your Supplier know the answers to the following questions:
– Are you trying to measure soil, water or another substance? There are all kinds of different electrodes, eg electrodes that won’t clog with oil, electrodes for measuring semi-solids and many different shapes / materials that will last longer for specific samples.
– If you tell your supplier what the application is, the best suited electrode can be chosen and this will lead to more accurate readings and a longer electrode life.
– See pH Electrodes to get an idea of some of the special applications available.
– pH readings are affected by the temperature of the sample you are testing. If you are not going to be always testing at room temperature, a meter with Automatic Temperature Compensation (ATC) is important for accurate measurements.
– High temperatures will also shorten the life of your electrode. Specialised glass / ceramic will be better than plastic.
– It is especially important to get a specialised electrode if you are measuring something with a temperature over 80°C, as a general use electrode will get damaged very quickly.
3. pH Range & Resolution / Accuracy
– The pH range is 0 – 14, some electrodes measure from 0 – 13 or 2 – 13.
– A basic pH meter will have a resolution of 0.0 – 14.0 and be less accurate but suitable for such uses as swimming pool water and aquaculture.
– Most pen-type pH meters will have a resolution of 0.00 – 14.00 and this is suitable for most water, food and beverage applications.
– Hand-held and bench-type meters are usually more sophisticated (and often more expensive) because they have greater accuracy and will measure to smaller decimal units, eg 0.000 – 14.000. These are often used in laboratories and / or for research purposes. Software connectivity is usually a consideration, too.
– Strong acidic / alkaline samples will require a special glass formulation – strong acid solutions will greatly shorten the life of a general purpose electrode
– Some electrodes are more durable then others for specific applications, eg some are designed to withstand dirt /oil or are more resistant to breaking.
– If you are taking measurements in the field, you may want to choose a more durable meter.
If in doubt, send us an email enquiry and we will recommend the best electrode for your application – there may be a specialty electrode that is better suited to your application that you are not aware of.
Once you have chosen a well-suited electrode, PLEASE DO read How to make your pH Electrode last longer. It is vital to know how to clean and store your special electrode.
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