In Situ Drift Monitoring and Calibration of Field-Deployed Potentiometric Sensors Using Temperature Supervision

Area of Science:

• Electrochemistry
• Sensor Technology
• Environmental Monitoring

Background:

• Potentiometric ion-selective electrodes (ISEs) are vital for various applications but suffer from voltage drift and require frequent calibration, hindering field deployment.
• Traditional calibration methods are impractical for field sensors due to the need for frequent recalibration with standard solutions and constant temperature conditions.

Purpose of the Study:

• To develop a novel in situ calibration approach for field-deployed ISEs that overcomes the limitations of traditional methods.
• To enable high-precision potentiometric sensing in variable temperature environments without sensor relocation or complex systems.

Main Methods:

• Proposed an in situ calibration method utilizing natural or external temperature variations to determine time-varying calibration parameters.
• Developed a temperature-supervised monitoring system to detect sensor drift during operation.
• Validated the approach through laboratory experiments with controlled temperature changes, greenhouse studies, and field monitoring of nitrate activity.

Main Results:

• Successfully reproduced calibration parameters for printed nitrate ISEs using the proposed method, demonstrating its viability as an alternative to traditional calibration.
• Utilized natural temperature fluctuations in a greenhouse to calibrate sensors and detect drift in nitrate solutions.
• Achieved high-precision nitrate activity monitoring in an agricultural field for 22 days, with results within 10% of laboratory measurements.

Conclusions:

• The developed temperature-based in situ calibration and drift monitoring methods enable accurate and reliable field sensing with ISEs.
• This approach significantly enhances the practicality and precision of potentiometric sensors in real-world, temperature-varying conditions.
• Highlights the potential for widespread adoption of this method in smart agriculture, environmental monitoring, and other field applications.