Characterization of porous polymer monoliths as flow restrictors for capillary electrophoresis on a chip

Yolanda Fintschenko*, Don Arnold, Eric Peters, Frank Svec, Jean Frechet

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


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 component, 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 μm wide×15 μm deep microchannel etched in glass. Our results indicate an average PPM pore size of 1 μm 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.

Original languageEnglish (US)
Pages (from-to)202-209
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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