Separation of aminophenol isomers in polyelectrolyte multilayers modified PDMS microchip.

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Polydimethylsiloxane (PDMS) microchips are widely used in microfluidic devices.
• Achieving efficient and rapid separation of closely related compounds like aminophenol isomers remains a challenge.
• Surface modification of PDMS is crucial for enhancing separation performance and stability.

Purpose of the Study:

• To develop a rapid and efficient method for separating aminophenol isomers.
• To investigate the use of polyelectrolyte multilayers (PEMs) for modifying PDMS microchips.
• To evaluate the impact of PEM modification on microchip performance, including electroosmotic flow (EOF) and sample adsorption.

Main Methods:

• Layer-by-layer assembly of polyelectrolyte multilayers (PEMs) using poly(diallyl dimethyl ammonium chloride) (PDDA) and poly(sodium-4-styrene-sulfonate) (PSS) on PDMS microchips.
• Electrochemical detection (EC) for analyzing separated aminophenol isomers.
• X-ray Photoelectron Spectroscopy (XPS) for surface characterization of the modified microchips.
• Optimization of separation conditions including running buffer pH, concentration, and separation voltage.

Main Results:

• Successful separation of three aminophenol isomers within 1 minute.
• PEM-modified PDMS microchips exhibited more stable electroosmotic flow (EOF) compared to native PDMS.
• Significantly reduced sample adsorption on PEM-modified microchips during electrophoresis.
• Achieved a 100-fold increase in column efficiency and a 2-fold enhancement in signal compared to native microchips.

Conclusions:

• Polyelectrolyte multilayer modification effectively enhances the performance of PDMS microchips for rapid separation of aminophenol isomers.
• The developed method offers a promising approach for sensitive and efficient analysis in microfluidic systems.
• The stable EOF and reduced adsorption contribute to improved separation efficiency and detection sensitivity.