Functionalization of micro- and nano-apertures with chromate-selective solvent polymeric membrane

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Miniaturization of analytical devices is crucial for in-situ and high-throughput measurements.
• Ion-selective electrodes (ISEs) are vital for detecting specific ions in various matrices.
• Developing micro- and nanoscale ISEs presents challenges in fabrication and performance.

Purpose of the Study:

• To demonstrate a novel miniaturization approach for creating micro- and nanoscale ion-selective electrodes (ISEs).
• To test the performance of these miniaturized ISEs using an environmentally relevant chromate-selective membrane.
• To evaluate the potential impact of these devices in microscale analytical processes.

Main Methods:

• Fabrication of micro- and nanoscale apertures (100 nm and 30 µm) using MEMS techniques.
• Functionalization of apertures with a solvent polymeric membrane (Aliquat336:2-NPOE:PVC).
• Performance characterization including response slope, limit of detection (LOD), response time, and electrical resistance.

Main Results:

• Nanoscale ISEs exhibited a response slope of -65.2±4.2 mV decade⁻¹ and LOD of 1.8 x 10⁻⁵±6 x 10⁻⁶ M.
• Microscale ISEs showed a response slope of -58.6±5.6 mV decade⁻¹ and LOD of 2.1 x 10⁻⁵±1.1 x 10⁻⁵ M.
• Response times were rapid (10-20 s) with high electrical resistance (GΩ range).

Conclusions:

• The demonstrated miniaturization approach is effective for creating high-performance micro- and nanoscale ISEs.
• These ISEs show promise for sensitive and rapid detection of chromate ions in environmental samples.
• The developed technology is expected to significantly impact microscale analytical processes and environmental monitoring.