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High-Pressure Microvalves for Microfluidic Control
Funding: DOE
Integration of microscale fluidic elements, whether for incorporating several element primitives to make a complicated device or for massively parallelizing a microfluidic analysis, is essential for reaching the potential for microfluidics to generate better, faster, and cheaper chemical/biochemical analysis (so-called Lab-on-a-Chip or BioMEMS devices. Complex fluid flow control and topology requires that microvalves be used to open and close fluidic pathways.

Many microfabricated valves have been proposed; however, proposed microvalves in general are unsuitable for controlling flows at high pressures (>20 atm) and cannot be used for high-pressure liquid chromatography (HPLC), the most common technique used for separating and analyzing chemicals.

We have developed techniques for laser-fabricating fluoropolymer switches in microchannels by photopolymerizing fluoroacrylate monomers with Nd:YAG lasers and projection optics. Our technique uniquely enables fabrication of microvalves that operate successfully in the harsh environment (high pressure, varying solvents) used for HPLC analysis.

Recent developments in high-pressure microvalves have allowed us to demonstrate high-pressure injection of subnanoliter volumes for HPLC analysis and explore miniaturized HPLC separations and links to mass spectrometry. We are interested, also, in other systems that require high surface-area-to-volume ratios, such as catalytic conversion of biofuels.

Publications and Presentations on High-Pressure Microfluidic Control

PDF version of Reichmuth, Shepodd, Kirby: Microchip HPLC of peptides and proteins

D.S. Reichmuth, T.J. Shepodd, B.J. Kirby
"Microchip HPLC of peptides and proteins," Analytical Chemistry 77:2997-3000 (2005). pdf text

PDF version of Kirby, Reichmuth, Renzi, Shepodd, Wiedenman: Microfluidic routing of aqueous and organic flows at high pressure: Fabrication and characterization of integrated polymer microvalve elements

B.J. Kirby, D.S. Reichmuth, R.F. Renzi, T.J. Shepodd, B.J. Wiedenman
"Microfluidic routing of aqueous and organic flows at high pressure: Fabrication and characterization of integrated polymer microvalve elements," Lab on a Chip 5:184-190 (2005). pdf text

PDF version of Reichmuth, Chirica, Kirby: Analysis of peptides using an integrated microchip HPLC-MS/MS system

D.S. Reichmuth, G.S. Chirica, B.J. Kirby
"Analysis of peptides using an integrated microchip HPLC-MS/MS system," in MicroTAS 2004, Kluwer Academic Publishers (2004). pdf

PDF version of Reichmuth, Shepodd, Kirby: On-chip high-pressure picoliter injector for pressure-driven flow through porous media

D.S. Reichmuth, T.J. Shepodd, B.J. Kirby
"On-chip high-pressure picoliter injector for pressure-driven flow through porous media," Analytical Chemistry 76:5063-5068 (2004). pdf text

PDF version of Reichmuth, Shepodd, Kirby: RP-HPLC microchip separations with subnanoliter on-chip pressure injections

D.S. Reichmuth, T.J. Shepodd, B.J. Kirby
"RP-HPLC microchip separations with subnanoliter on-chip pressure injections," in MicroTAS 2003, Kluwer Academic Publishers (2003). pdf

PDF versino of Fintschenko, Kirby, Hasselbrink, Singh, Shepodd: Monolithic materials: miniature and microchip technologies

Y. Fintschenko, B.J. Kirby, E.F. Hasselbrink, A.K. Singh, T.J. Shepodd
"Monolithic Materials: Miniature and Microchip Technologies," in Monolithic Materials: Preparation, Properties, and Applications Elsevier, Amsterdam (2003). pdf

PDF version of Kirby, Shepodd, Hasselbrink: Voltage-addressable on/off microvalves for high-pressure microchip separations

B.J. Kirby, T.J. Shepodd, E.F. Hasselbrink
"Voltage-Addressable On/Off Microvalves for High-Pressure Microchip Separations," Journal of Chromatography A 979:147-154 (2002). pdf

PDF version of Kirby, Shepodd: Microvalve architectures for high-pressure hydraulic and electrokinetic fluid control in microchips

B.J. Kirby, T.J. Shepodd
"Microvalve Architectures for High-Pressure Hydraulic and Electrokinetic Fluid Control in Microchips," in MicroTAS 2002, Kluwer Academic Publishers, pp. 338-340 (2002). pdf

Manifold for multi-port high-pressure fixturing (click here for source). These devices enable fabrication and interfacing of high-pressure microfluidic systems.
A high-pressure microfluidic valve produced by polymerizing a fluoroacrylate polymer inside a fused silica microsystem (click here for source).