Solid Contact Ion-Selective Electrodes for in Situ Measurements at High Pressure

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Monitoring

Background:

• Traditional ion-selective electrodes (ISEs) face limitations in high-pressure environments.
• Solid contact ISEs (SC-ISEs) offer potential for improved sensor stability and performance.
• Microporous carbon (μPC) is explored as an ion-to-electron transducer in SC-ISEs.

Purpose of the Study:

• To develop and characterize novel SC-ISEs using μPC for high-pressure applications.
• To evaluate the performance of potassium-selective ISEs (K+-ISEs) under elevated pressures.
• To assess the feasibility of using these SC-ISEs for in situ measurements in deep-sea environments.

Main Methods:

• Fabrication of SC-ISEs with μPC transducer and a liquid membrane cocktail.
• Characterization of SC-ISEs in aqueous environments up to 100 bar.
• Performance evaluation including response slopes, potential stability, sensitivity, and limit of detection.
• Calibration in standard solutions and simulated seawater under high pressure.

Main Results:

• SC-ISEs demonstrated suitability for analysis at pressures up to 100 bar.
• Potassium ISEs exhibited excellent performance and stability at both atmospheric and elevated pressures.
• These novel SC-ISEs successfully measured K+ at pressures where traditional ISEs failed.
• Pressure had minimal impact on the sensors' potential, sensitivity, or limit of detection.

Conclusions:

• Novel SC-ISEs utilizing microporous carbon are effective for high-pressure potassium ion measurements.
• These sensors offer significant advantages over traditional ISEs in demanding environments.
• The developed SC-ISEs show promise for in situ, real-time ion-flux measurements in deep-ocean settings, such as near geothermal vents.