Recalibrating ion selective electrodes by catching their drift

What is it about?

Ion selective electrode (ISE) systems are electric systems where only a specific ion (or charged particle) is used to create electric current. ISE sensors measure pH changes in solutions. Silver chloride is a commonly used material in these systems. However, this material has a drawback: there is a drift (or a gradual breakdown and change in electrode response) over time. “Calibrating” this drift, or bringing the values back to standard, is difficult. The redox reaction of anthraquinone is sensitive to this drift. This reaction can be used to track the drift in real time. So, researchers used this reaction to study the breakdown of silver chloride electrode. Using this information, they recalibrated the ISE system.

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Photo by Marek Piwnicki on Unsplash

Photo by Marek Piwnicki on Unsplash

Why is it important?

pH is a measure of acidity. Changes in pH can show the presence of pollutants and chemicals in water. Growing environmental concerns mean that chemical sensors are becoming more important. Current ISEs need consistent recalibration due to electrode drift. The high maintenance cost limits the industrial use of ISEs. This new ISE system does not need calibration or expensive field visits and lasts longer than current ISEs. These changes help reduce the maintenance costs, which can save up to 70% of the total cost. More stable and accurate systems will allow a wider application of ISEs in industry and help this technology scale up. KEY TAKEAWAY: This innovative approach allows for internal automatic recalibration of ISEs. Potential drift in the reference electrode can be corrected by tracking it in real time.