Ion-selective electrodes: General tips – Part 1
21.02.2022
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This article is Part 1 of a series.
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Part 2Ions – we encounter these tiny charge carriers constantly. Depending on the concentration of certain anions (negative ions) and cations (positive ions), they can have a significant impact on humans and the environment. Thanks to ongoing quality control in several industries such as food and beverage, the metallurgical industry, and water management, defined limits are neither exceeded nor undercut.
So, how can these small, ubiquitous ions be determined? Mistakenly, I thought at first that ion measurement is only possible by means of more costly analytical methods such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES), or atomic absorption spectroscopy (AAS). A promising cost-efficient alternative to these techniques is to use so-called ion-selective electrodes (ISE).
If you are interested in one or more of these subjects:
- which ion-selective electrodes are available
- the basic theory behind ion-measurement
- why a TISAB or ISA solution needs to be added for the measurement
- what is the best way to care for your ISE
…then you have come to the right place.
Types of ion-selective electrodes
If you want to determine, for example, the fluoride concentration in your toothpaste, the ammonium content of the water in your aquarium, or perhaps how much calcium is really in a fruit juice, then there are many suitable ion-selective electrodes for your application needs. Check out our free Application Bulletins on these subjects below for further information.
Determination of fluoride with an ion-selective electrode
Complexometric titrations with the copper ion-selective electrode
Membrane material
The very first ion-selective electrode was the pH electrode. However, this article will not discuss pH electrodes—you can find more information in our other posts pertaining to this special ISE.
Avoiding the most common mistakes in pH measurement
Aside from the glass membrane used for pH electrodes, there are other membrane materials available for selective measurement of myriad ions. The most widely applied types are listed in Table 1.