50-Fold Reduction of Separation Time in Open-Channel Hydrodynamic Chromatography via Lateral Vortices

Area of Science:

• Analytical Chemistry
• Fluid Dynamics
• Chromatography

Background:

• Open-channel hydrodynamic chromatography (OC-HDC) is a niche technique for particle size distribution analysis.
• Low eluent velocity in OC-HDC causes Taylor-Aris dispersion, limiting practical application.
• Micrometric channel sizes necessitate low flow rates (pL/min), challenging injection and detection.

Purpose of the Study:

• To investigate the theoretical/numerical evidence for reducing Taylor-Aris dispersion in OC-HDC.
• To explore the use of cross-sectional vortices to enhance OC-HDC performance.
• To analyze particle separation efficiency using a novel vortex-induced method.

Main Methods:

• Theoretical and numerical modeling of fluid flow and particle transport.
• Utilizing DC-induced electroosmosis to generate lateral vortices in a square channel.
• Applying the excluded-volume macrotransport approach for particle velocity and dispersion analysis.

Main Results:

• Cross-sectional vortices significantly reduce the Taylor-Aris dispersion effect.
• The vortex-enhanced OC-HDC method improves separation efficiency.
• A 50-fold reduction in separation time for a two-species mixture was achieved compared to standard OC-HDC.

Conclusions:

• Triggering cross-sectional vortices offers a viable strategy to overcome OC-HDC limitations.
• This approach enhances particle separation and reduces analysis time, making OC-HDC more practical.
• The findings pave the way for improved particle analysis techniques.