A low pressure on-chip injection strategy for high-performance chip-based chromatography.

Area of Science:

• Analytical Chemistry
• Microfluidics
• Chromatography

Background:

• Microfluidic devices offer miniaturization advantages for analytical separations.
• Traditional High-Performance Liquid Chromatography (HPLC) often requires significant sample volumes and expensive equipment.
• Integrating chromatographic functions onto a chip can enhance efficiency and reduce costs.

Purpose of the Study:

• To develop and demonstrate a microfluidic chip for high-performance liquid chromatography (HPLC).
• To enable efficient chromatographic separations using conventional HPLC instrumentation.
• To present an on-chip sampling strategy for precise sample plug definition.

Main Methods:

• Fabrication of a borosilicate glass microfluidic chip with integrated injector and column chamber.
• Utilizing the keystone effect for particle retention within the column.
• Employing laser-assisted photopolymerization for permanent sealing of the packing channel.
• Implementing an on-chip flow splitting strategy for sample introduction.
• Characterization via video microscopy and chromatographic separation of polycyclic aromatic hydrocarbons (PAHs).

Main Results:

• Successful integration of chromatographic column and injector on a single chip.
• Demonstrated retention of 3-μm particles using the keystone effect.
• Elimination of dead volumes through laser-assisted photopolymerization.
• Achieved high chromatographic efficiencies for PAH separations using standard HPLC systems.
• Validated an on-chip sampling strategy for controlled injection.

Conclusions:

• The developed microfluidic HPLC chip provides a high-performance, cost-effective alternative to traditional methods.
• The on-chip flow splitting and sampling strategy allows for the use of economic HPLC instrumentation.
• This approach offers robust and efficient separations suitable for various analytical applications.