Improving your conductivity measurements
Apr 6, 2020
Article
Have you ever performed a conductivity measurement and obtained incorrect results? There are several possible reasons for this. In this post, I want to show you how you may overcome some of these issues.
By itself, conductivity measurement is performed quite easily. One takes a conductivity cell and a suitable measuring device, inserts the conductivity cell into the sample solution and reads the value given. However, there are some challenges such as choosing the right sensor, the temperature dependency of conductivity, or the CO2 uptake, which falsify your results.
The following topics will be covered in the rest of this post (click to jump to the topic):
So many measuring cells – which one to use?
The first and most important question about conductivity measurement is: which sensor is the most suitable for your application? The measuring range is dependent on the cell constant of your conductivity cell, and therefore this choice requires a few considerations:
- What is the expected conductivity of my sample?
- Do I have a broad range of conductivities within my samples?
- What is the amount of sample I have available for measurement?
There are different types of conductivity measuring cells available on the market. Two-electrode cells have the advantage that they can be constructed within a smaller geometry, and are more accurate at low conductivities. On the other hand, other types of measuring cells show no influences towards polarization, have a larger linear range, and are less sensitive towards contaminations.