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Trapping of bead-based reagents within microfluidic systems: on-chip solid-phase extraction and electrochromatography
Oleschuk1, Shultz-Lockyear, Ning
1Department of Chemistry, University of Alberta, Edmonton, Canada.
Analytical Chemistry
|March 1, 2000
Summary
This study presents a microfluidic system for repeated analyte concentration using octadecylsilane (ODS) beads. The system achieved up to 500x concentration enhancement for nonpolar analytes, demonstrating its potential in analytical chemistry.
Area of Science:
- Analytical Chemistry
- Microfluidics
- Chromatography
Background:
- Microfluidic systems offer miniaturized platforms for chemical analysis.
- Efficient sample preparation and analyte enrichment are crucial for sensitive detection.
Purpose of the Study:
- To develop a microfluidic system for on-chip, repeated concentration of analytes using electroosmotic flow (EOF).
- To demonstrate the capability of the system for sample enrichment and subsequent capillary electrochromatography (CEC).
Main Methods:
- Fabrication of a 330-pL chromatographic bed on a glass substrate with weirs to trap octadecylsilane (ODS) coated silica beads.
- Mobilization of ODS beads using EOF for repeated exchange within the cavity.
- Loading of a nonpolar analyte (BODIPY 493/503) onto ODS beads via EOF.
- Elution of the analyte using EOF with an acetonitrile/buffer mobile phase.
- Separation of BODIPY and fluorescein using CEC in a similar device.
Main Results:
- Achieved concentration enhancement of up to 500 times for a nonpolar analyte.
- Demonstrated efficient loading and elution of analytes using EOF.
- Successfully separated BODIPY and fluorescein in less than 20 seconds with a 2-micron plate height in CEC.
Conclusions:
- The developed microfluidic system enables repeated analyte concentration and enrichment.
- The system is suitable for integration with capillary electrochromatography for sensitive and rapid separations.