Ion-Selective Electrode for Nitrates Based on a Black PCV Membrane.

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Polymeric membranes are crucial for ion-selective electrodes.
• Carbon nanomaterials offer unique electrical and surface properties.
• Improving sensor performance and simplifying fabrication are key challenges.

Purpose of the Study:

• To investigate the effect of incorporating carbon nanomaterials into polymeric membranes for nitrate sensors.
• To evaluate the electrochemical performance and stability of modified single-piece electrodes.
• To assess the impact of carbon nanomaterials on sensor preparation procedures.

Main Methods:

• Potentiometry
• Chronopotentiometry
• Electrochemical impedance spectroscopy
• Modification of polymeric membranes with graphene, carbon black, and carbon nanotubes.

Main Results:

• Carbon nanomaterials significantly improved potentiometric response without redox activity.
• Near-Nernstian response (54 mV/pNO₃^-) observed over a wide linear range (10^-1 to 10^-6 M NO₃^-).
• High capacitance (0.9 mF for graphene) led to stable potentiometric response and low potential drift (0.065 mV/h).

Conclusions:

• Incorporating carbon nanomaterials into polymeric membranes enhances nitrate sensor performance.
• The modified single-piece electrodes exhibit excellent sensitivity, stability, and a simplified preparation process.
• This approach offers a promising route for developing efficient and easily fabricated nitrate-selective sensors.