Potentiometric sensing array for monitoring aquatic systems

Area of Science:

• Environmental Science
• Analytical Chemistry
• Sensor Technology

Background:

• Aquatic environments require continuous monitoring due to their dynamic nature.
• Traditional sampling methods lack the spatial and temporal resolution needed for effective ecosystem management.
• Automated techniques are crucial for real-time data acquisition in aquatic systems.

Purpose of the Study:

• To develop and validate an autonomous potentiometric sensing array for continuous monitoring of freshwater ecosystems.
• To assess the array's capability in measuring nutrients and carbon cycle species with high resolution.
• To compare field data from the automated system with traditional laboratory analyses.

Main Methods:

• Development of a self-contained instrument integrating measurement, calibration, and fluidic control.
• Deployment of a potentiometric sensing array using polymeric membrane materials.
• Field validation on an automated platform in Lake Greifensee, Switzerland.
• Use of ion-selective electrodes (ISEs) for hydrogen ions, carbonate, calcium, nitrate, and ammonium.

Main Results:

• Demonstrated linear correlation between ISE-measured calcium and nitrate activities and laboratory concentrations.
• Calculated apparent single ion activity coefficients for calcium and nitrate.
• Achieved good correlation between ISE-measured pH and CTD probe measurements, indicating reliability.
• The automated system provided high spatial and temporal resolution data.

Conclusions:

• The developed potentiometric sensing array offers a reliable and autonomous solution for continuous monitoring of freshwater ecosystems.
• The system effectively measures key chemical species relevant to the carbon cycle.
• This technology enhances aquatic ecosystem monitoring by providing high-resolution data, complementing traditional methods.