Development of long-term stable reference electrode with fluoric resin liquid junction.

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Conventional reference electrodes often suffer from limited lifespan and sensitivity to pressure changes.
• Maintaining a stable inner solution in reference electrodes is crucial for accurate flow analysis.
• Existing porous ceramic junctions have small pore sizes, leading to higher solution leakage.

Purpose of the Study:

• To develop a novel porous polytetrafluoroethylene (PTFE) junction reference electrode for flow analysis.
• To investigate the performance and longevity of the PTFE reference electrode compared to conventional ceramic junctions.
• To assess the stability and operational parameters of the new electrode design.

Main Methods:

• Fabrication of porous PTFE using PTFE and potassium chloride (KCl) powders, followed by pressing and sintering.
• Characterization of the PTFE junction pore size (approx. 150 µm) and KCl exudation rate.
• Evaluation of junction potential stability across a range of pH and ionic strengths.

Main Results:

• The developed PTFE reference electrode exhibits significantly reduced KCl exudation (10-6 mol h-1) compared to ceramic junctions.
• The electrode demonstrates stable junction potential in pH 2-12 and ionic strength > 10-3 mol l-1.
• The air-tight design is unaffected by sample pressure changes, eliminating the need for continuous KCl replenishment.

Conclusions:

• The porous PTFE reference electrode offers a long-lasting and stable solution for flow analysis.
• Its unique properties, including large pore size and high surface tension, prevent overflow and minimize solution loss.
• This innovative electrode design provides a reliable and low-maintenance alternative for electrochemical measurements.