Improved Lead Sensing Using a Solid-Contact Ion-Selective Electrode with Polymeric Membrane Modified with Carbon...

Area of Science:

• Electroanalytical Chemistry
• Materials Science
• Environmental Sensing

Background:

• Solid-contact ion-selective electrodes (ISEs) are crucial for ion detection.
• Developing sensitive and selective electrodes for lead (II) ions remains a challenge.
• Nanocomposite materials offer potential for enhancing electrode performance.

Purpose of the Study:

• To develop and characterize a new solid-contact ion-selective electrode (ISE) for lead (II) ions.
• To investigate the effect of a carbon nanofiber and ionic liquid nanocomposite on electrode properties.
• To evaluate the analytical performance and stability of the modified ISE.

Main Methods:

• Fabrication of ISEs with polymer membranes modified by a nanocomposite (carbon nanofibers and 1-hexyl-3-methylimidazolium hexafluorophosphate).
• Electrode characterization using potentiometric and electrochemical impedance spectroscopy.
• Testing electrodes with varying nanocomposite content (0-9% w/w) and internal electrodes (platinum wire or glassy carbon).

Main Results:

• Nanocomposite modification decreased membrane resistance and increased capacitance and hydrophobicity.
• Modified electrodes showed lower detection limits, wider measuring ranges, and better selectivity than unmodified ones.
• The optimal electrode (6% nanocomposite, platinum wire internal) exhibited a Nernstian response (31.5 mV/decade) from 1.0 × 10⁻⁸ to 1.0 × 10⁻² mol L⁻¹, with a detection limit of 6.0 × 10⁻⁹ mol L⁻¹.

Conclusions:

• The developed solid-contact ISE with a nanocomposite membrane demonstrates superior performance for lead (II) ion detection.
• The electrode offers excellent stability, reversibility, and resistance to redox potential changes.
• The sensor successfully analyzed lead content in a real sample, indicating practical applicability.