Study of the electroosmotic flow as a means to propel the mobile phase in capillary electrochromatography in view of further miniaturization of capillary electrochromatography systems

Title data

Szekely, Laszlo ; Freitag, Ruth:
Study of the electroosmotic flow as a means to propel the mobile phase in capillary electrochromatography in view of further miniaturization of capillary electrochromatography systems.
In: Electrophoresis. Vol. 26 (2005) Issue 10 . - pp. 1928-1939.
ISSN 1522-2683
DOI: https://doi.org/10.1002/elps.200410194

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Abstract in another language

In this paper, we investigate the phenomenon of electroosmosis as a means to propel a mobile phase, in particular in view of an application in microfluidic systems, which are characterized by significantly smaller volumes of the reservoirs and the separation channels compared to conventional instrumentation. In the microfluidic chip, pH changes due to water electrolysis quickly showed an effect on the electroosmotic flow (EOF), which could be counteracted by either regularly exchanging or buffering the mobile phase. Surface treatment was of no effect in regard to EOF stabilization in empty channels but may have an influence in channels filled with a charged monolith. In fused-silica capillaries the EOF was generally found to decrease from ‘naked’ to surface-treated to monolith-filled capillaries. The EOF tended to be higher when an organic solvent (acetonitrile) was added to the mobile phase and could be further increased by substituting the water with equal amounts of methanol. In addition, the hydrostatic pressure exerted by the EOF was investigated. In a microfluidic chip with empty (cross-)channels such an effect could be responsible for a redirection of the flow. In capillaries partially filled with a noncharged (non-EOF-generating) monolith, a linear relationship could be established between the EOF created in the empty section of the capillary (apparent mobility) and the length of the monolith (backpressure). In capillaries partially filled with a charged (EOF-producing) monolith, flow inhomogeneities must be expected as a consequence of a superimposition of hydrodynamic pressure and EOF as mobile phase driving force.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Keywords:	Capillary electrochromatography; Electroosmotic flow; Microanalytical system; Mobile phase
Institutions of the University:	Faculties > Faculty of Engineering Science > Chair Process Biotechnology > Chair Process Biotechnology - Univ.-Prof. Dr. Ruth Freitag Faculties Faculties > Faculty of Engineering Science Faculties > Faculty of Engineering Science > Chair Process Biotechnology
Result of work at the UBT:	No
DDC Subjects:	500 Science 500 Science > 500 Natural sciences 600 Technology, medicine, applied sciences 600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited:	25 Feb 2016 14:32
Last Modified:	25 Feb 2016 14:32
URI:	https://eref.uni-bayreuth.de/id/eprint/31057