High efficiency hydrodynamic chromatography in micro- and sub-micrometer deep channels using an on-chip...

Area of Science:

• Analytical Chemistry
• Microfluidics
• Chromatography

Background:

• Microchip-based separation techniques offer miniaturization and portability.
• Hydrodynamic chromatography (HDC) is a size-based separation method.
• Generating controlled flow in microfluidic devices is crucial for chromatographic applications.

Purpose of the Study:

• To develop a microchip-based hydrodynamic chromatography device with an integrated pressure generation unit.
• To achieve efficient size-based particle separations using microchip HDC.
• To investigate the performance of the device across different channel depths.

Main Methods:

• Fabrication of a microchip with two glass channel segments of different depths.
• Introduction of electroosmotic flow mismatch to generate a pressure gradient.
• Guiding a fraction of the pressure-driven flow into an analysis channel for particle separation.
• Separation of polystyrene beads (25, 100, 250 nm) using the microchip device.

Main Results:

• Successful implementation of microchip hydrodynamic chromatography with integrated pressure generation.
• Pressure-driven velocities were largely unaffected by scaling down channel depth.
• Achieved high separation efficiencies (500-2000 plates/mm) for nanoparticles.
• Demonstrated rapid analysis times as short as 12 seconds.

Conclusions:

• The developed microchip HDC device enables efficient and rapid size-based particle separation.
• The integrated pressure generation system is robust and scalable to micro- and sub-micrometer channel depths.
• This technology surpasses previous microchip HDC methods in separation efficiency and speed.