A Closed-loop, Non-linear, Miniaturised Capillary Electrophoresis System Enabled by Control of Electroosmotic Flow
A Closed-loop, Non-linear, Miniaturised Capillary Electrophoresis System Enabled by Control of Electroosmotic Flow
The miniaturisation of capillary electrophoresis (CE) systems makes separation of ionic species with similar electrophoretic mobilities challenging. We report on a novel closed-loop system that does not rely on migration time to identify ionic species unlike many conventional CE systems. To aid miniaturisation our method requires the sample undergoing separation to travel back and forth along the short channel multiple times. For each consecutive cycle the sample becomes increasingly separated until it is deemed sufficiently separated such that it can be reliably identified by any appropriate detection system. As the sample approaches either of the channel ends, contactless conductivity detectors detect the presence of the sample and trigger the modification of the electroosmotic flow (EOF) to reverse the direction of flow in the channel. After sufficient separation the identification is performed in-channel using, in our case, an electrochemical detection scheme. Incorporation of a closed-loop control system means that unpredictable variation in migration time does not present an issue for ionic species identification. This new method of non-linear CE is demonstrated in a microfluidic channel formed in PDMS (polydimethylsiloxane), reversibly sealed to a glass wafer on which metal electrodes are patterned in gold. The sample movement in both directions along the channel occurs without affecting the electrophoretic separation already achieved during each cycle by changing the EOF in magnitude and direction. The EOF is changed by modifying the zeta-potential along the channel wall through the application of a voltage on a zeta-potential modification (ZPM) electrode placed close to the channel surface. Depending on the magnitude and polarity of the voltage applied to the ZPM electrode our experiments have shown the ability to increase, decrease or reverse the EOF.
Lewis, Adam
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Cranny, Andrew
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Green, Nicolas
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Harris, Nick
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Stokes, Keith
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Wharton, Julian
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Wood, Robert
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Lewis, Adam
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Cranny, Andrew
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Green, Nicolas
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Harris, Nick
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Stokes, Keith
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Wharton, Julian
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Wood, Robert
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Lewis, Adam, Cranny, Andrew, Green, Nicolas, Harris, Nick, Stokes, Keith, Wharton, Julian and Wood, Robert
(2011)
A Closed-loop, Non-linear, Miniaturised Capillary Electrophoresis System Enabled by Control of Electroosmotic Flow.
The 15th International Symposium on Field- and Flow-based Separations (FFF 2011), San Francisco.
23 - 25 May 2011.
(Submitted)
Record type:
Conference or Workshop Item
(Poster)
Abstract
The miniaturisation of capillary electrophoresis (CE) systems makes separation of ionic species with similar electrophoretic mobilities challenging. We report on a novel closed-loop system that does not rely on migration time to identify ionic species unlike many conventional CE systems. To aid miniaturisation our method requires the sample undergoing separation to travel back and forth along the short channel multiple times. For each consecutive cycle the sample becomes increasingly separated until it is deemed sufficiently separated such that it can be reliably identified by any appropriate detection system. As the sample approaches either of the channel ends, contactless conductivity detectors detect the presence of the sample and trigger the modification of the electroosmotic flow (EOF) to reverse the direction of flow in the channel. After sufficient separation the identification is performed in-channel using, in our case, an electrochemical detection scheme. Incorporation of a closed-loop control system means that unpredictable variation in migration time does not present an issue for ionic species identification. This new method of non-linear CE is demonstrated in a microfluidic channel formed in PDMS (polydimethylsiloxane), reversibly sealed to a glass wafer on which metal electrodes are patterned in gold. The sample movement in both directions along the channel occurs without affecting the electrophoretic separation already achieved during each cycle by changing the EOF in magnitude and direction. The EOF is changed by modifying the zeta-potential along the channel wall through the application of a voltage on a zeta-potential modification (ZPM) electrode placed close to the channel surface. Depending on the magnitude and polarity of the voltage applied to the ZPM electrode our experiments have shown the ability to increase, decrease or reverse the EOF.
Text
Abstract.pdf
- Accepted Manuscript
Text
Final Draft of Poster for FFF2011 (Adam Lewis).pdf
- Other
More information
Submitted date: 7 February 2011
Additional Information:
Event Dates: 23/05/11 - 25/05/11
Venue - Dates:
The 15th International Symposium on Field- and Flow-based Separations (FFF 2011), San Francisco, 2011-05-23 - 2011-05-25
Organisations:
Nanoelectronics and Nanotechnology, EEE
Identifiers
Local EPrints ID: 272138
URI: http://eprints.soton.ac.uk/id/eprint/272138
PURE UUID: df5b475a-0ff8-41b2-b361-b16f01086b71
Catalogue record
Date deposited: 04 Apr 2011 11:57
Last modified: 15 Mar 2024 03:20
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Contributors
Author:
Adam Lewis
Author:
Andrew Cranny
Author:
Nicolas Green
Author:
Nick Harris
Author:
Julian Wharton
Author:
Robert Wood
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