The determination of sodium using an ion-selective electrode is a relatively inexpensive and accurate method. It requires some skill and careful preparation to manage matrix effects. It is particularly sensitive with detection possible in concentrations less than 1 µg/l with meticulous care. We discuss sample collection through to measurement and analysis.
John has worked in the field of analytical chemistry for over 45 years and has gained experience in a wide variety of analytical techniques and instrumentation in several industries and applications. He has always been interested in understanding the technology well and utilizing it at its optimum in order to produce reliable and accurate chemical data. To this end he is committed to enable others to not only use the technology correctly but also understand what it does, how it works and how to maintain it.
The topic of sodium measurement is introduced, the theory is explained (very similar to that of pH measurement) and the electrodes and their construction described.
Water and other samples are easily contaminated with respect to sodium, so some correct practices and habits are introduced. The section proceeds with preparation of standards and samples for calibration, and the calibration itself followed by measurement.
The last section addresses care and maintenance of equipment followed by troubleshooting. Some guidance on field (portable) measurement is given.