Conductometric sensor for potassium ion profiling using lipophilic salt-incorporated non-toxic ion-selective membrane

Area of Science:

• Electrochemistry
• Chemical Sensors
• Materials Science

Background:

• Conventional potentiometric ion-selective electrodes (ISEs) face limitations in miniaturization and real-time monitoring.
• Existing potassium-selective electrodes often rely on toxic components like valinomycin.
• There is a need for safer, more efficient ISEs for bioanalytical applications.

Purpose of the Study:

• To develop and characterize a novel, non-toxic conductometric potassium-selective electrode (ISE) using a new ionophore.
• To evaluate the sensor's performance, including sensitivity, selectivity, and dynamic range.
• To compare the performance of the new conductometric ISE with existing potentiometric ISEs.

Main Methods:

• Incorporation of a non-toxic potassium ionophore (K-III) into a PVC-based ion-selective membrane (ISM).
• Deposition of the ISM onto gold interdigitated electrodes for impedance-based measurements.
• Optimization of sensor performance by adjusting lipophilic salt concentration (KTpClPB).
• Evaluation of selectivity using Separate Solution Method (SSM) and Fixed Interference Method (FIM).

Main Results:

• The K-III-based conductometric ISE demonstrated tunable sensitivity, selectivity, and dynamic range.
• Optimized sensors showed a threefold higher response compared to toxic valinomycin-based ISEs.
• Selectivity coefficients confirmed excellent potassium selectivity, comparable to established potentiometric ISEs.
• The non-toxic nature of the K-III ionophore enhances safety.

Conclusions:

• K-III-based conductometric ISEs represent a promising, non-toxic alternative for potassium detection.
• These sensors offer advantages in miniaturization, real-time monitoring, and reduced calibration.
• The developed ISEs are suitable for accurate potassium analysis in complex bioanalytical environments.