Impedance-based sensor for potassium ions.

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Potassium ion (K+) measurement is crucial in clinical diagnostics.
• Existing methods for potassium detection can be complex or require reference electrodes.
• Development of miniaturized, robust sensors for in-situ potassium monitoring is needed.

Purpose of the Study:

• To develop and characterize a novel conductometric sensor for potassium ions.
• To optimize sensor performance, including sensitivity and selectivity.
• To demonstrate the sensor's utility in a clinically relevant concentration range.

Main Methods:

• Fabrication of interdigitated planar gold electrodes.
• Coating electrodes with a polymer membrane (poly(vinyl chloride), plasticizer, potassium-selective ionophore).
• Impedance measurements of the membrane to correlate with potassium ion concentration.

Main Results:

• The sensor demonstrated sensitivity to potassium ion concentration.
• High selectivity for potassium ions over sodium ions was achieved.
• The sensor successfully operated without a reference electrode.
• Performance was validated across the clinically relevant range of 2.7-18.7 mM.

Conclusions:

• A compact, miniature, and robust conductometric sensor for potassium ions was successfully developed.
• Impedance measurements provide a viable method for potassium detection without a reference electrode.
• The sensor shows promise for point-of-care or in-line monitoring applications.