Radially Aligned Carbon Nanotube Glass Fiber Composites as Ion-Selective Microelectrodes

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Potentiometric ion-selective electrodes (ISE) are valuable for cost-effective, user-friendly, and miniaturized ion detection.
• Challenges in ion detection include small size, rapid diffusion, and high mobility, particularly in low-volume samples.

Purpose of the Study:

• To investigate radially aligned carbon nanotubes (RACNT) grown on glass fibers (GF) as a solid contact material for ion-selective microelectrodes (μISE).
• To evaluate the performance of RACNT-GF based μISE for sensitive and selective ion detection compared to conventional ISE.

Main Methods:

• Fabrication of μISE using RACNT-GF as the solid contact material, incorporating ionophores within a polymeric membrane.
• Utilizing chemical vapor deposition for growing RACNT directly on GF.
• Potentiometric measurements to assess limit of detection (LOD) and linear response range.

Main Results:

• The fabricated μISE with RACNT-GF demonstrated improved LOD and enhanced selectivity for ammonium ion detection compared to graphite-based ISE.
• A limit of detection (LOD) of 7.5 × 10^-6 M and a linear response range from 1.0 × 10^-5 to 1.0 × 10^-1 M were achieved for ammonium ions.
• The high surface area and mechanical durability of RACNT-GF contribute to maximized ionophore accommodation and improved potentiometric responses.

Conclusions:

• RACNT-GF composites are effective solid contact materials for developing sensitive and selective ion-selective microelectrodes.
• The developed μISE show significant potential for on-site and miniaturized ion analysis.
• This approach offers a promising pathway for fabricating advanced potentiometric sensors with enhanced performance.