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Proceedings Paper

Characterization of porous polymer monoliths as flow restrictors for capillary electrophoresis on a chip
Author(s): Yolanda Fintschenko; Don W. Arnold; Eric C. Peters; Frank Svec; Jean M. J. Frechet
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Paper Abstract

Capillary electrophoresis (CE) lends itself to miniaturization, because it uses electroosmotic flow rather than moving parts for flow generation. Its analytical figures of merit improve as channel dimensions decrease. However, solution flow in the small planar channels used in CE-on-a-chip is very sensitive to reservoir solution height. This adds a pressure driven flow components, which decreases resolution, sensitivity, and separation efficiency of the EOF-driven technique. We have observed that this contribution to parabolic flow from uneven solution heights can be minimized by using a porous polymer monolith (PPM) as a flow restriction plug in the reservoirs of a 75 micrometers wide X 15 micrometers deep microchannel etched in glass. Our results indicate an average PPM pore size of 1 micrometers is sufficient for flow restriction. Pore sizes below this result in charge trapping of even small dye molecules. Images of the flow profile on and off the monolith show the inverse-parabolic effect on the electroosmotic flow profile due to mismatched zeta potentials between the polymer and the fused silica wall surfaces depending on PPM surface charge and plug length.

Paper Details

Date Published: 19 August 1999
PDF: 8 pages
Proc. SPIE 3877, Microfluidic Devices and Systems II, (19 August 1999); doi: 10.1117/12.359338
Show Author Affiliations
Yolanda Fintschenko, Sandia National Labs. (United States)
Don W. Arnold, Sandia National Labs. (United States)
Eric C. Peters, Univ. of California/Berkeley (United States)
Frank Svec, Univ. of California/Berkeley (United States)
Jean M. J. Frechet, Univ. of California/Berkeley (United States)

Published in SPIE Proceedings Vol. 3877:
Microfluidic Devices and Systems II
Chong Hyuk Ahn; A. Bruno Frazier, Editor(s)

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