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Title: Electrokinetic Sample Preconcentration and Hydrodynamic Sample Injection for Microchip Electrophoresis Using a Pneumatic Microvalve

A microfluidic platform was developed to perform online electrokinetic sample preconcentration and rapid hydrodynamic sample injection for electrophoresis using a single microvalve. The PDMS microchip consists of a separation channel, a side channel for sample introduction, and a control channel which is used as a pneumatic microvalve aligned at the intersection of the two flow channels. The closed microvalve, created by multilayer soft lithography, can serve as a preconcentrator under an applied electric potential, enabling current to pass through while blocking bulk flow. Once analytes are concentrated, the valve is briefly opened and the stacked sample is pressure injected into the separation channel for electrophoretic separation. Fluorescently labeled peptides were enriched by a factor of ~450 in 230 s. The performance of the platform was validated by the online preconcentration, injection and electrophoretic separation of fluorescently labeled peptides. This method enables both rapid analyte concentration and controlled injection volume for high sensitivity, high resolution capillary electrophoresis.
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1522-2683; 48204; KP1704020
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Electrophoresis; Journal Volume: 37; Journal Issue: 3
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
Electrokinetic; injection; capillary; electrophoresis; peumatic; microvalve; Environmental Molecular Sciences Laboratory