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Electrohydrodynamic instabilities and segregation of polysaccharides in capillary polymer solution electrophoresis
Author(s) -
Stefansson Morgan
Publication year - 1999
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(199905)49:6<515::aid-bip9>3.0.co;2-e
Subject(s) - electrohydrodynamics , chemistry , ionic strength , polymer , electric field , field strength , electrophoresis , debye length , capillary electrophoresis , analytical chemistry (journal) , chemical physics , capillary action , chromatography , thermodynamics , ion , aqueous solution , organic chemistry , electrode , physics , quantum mechanics , magnetic field
During capillary electrophoresis of negatively charged polysaccharides in polymer solutions as sieving media, concentration fluctuations develop due to electrohydrodynamic instabilities caused by polarization of the polyelectrolytic chains. This leads to deviations from electroneutrality far beyond the Debye layer and segregation of the initially homogeneous sample solution into aggregated sample‐rich domains as verified by epifluorescence videomicroscopy imaging. As a result, anomalous and irregular peak profiles are obtained impeding the characterization of such complex sample mixtures. This effect appears at an electric field strength threshold value that depends on the molecular weight of the solute polymer molecules, pH, type and concentration of the polymer solution sieving media, and buffering conditions. The magnitude increases with increasing field strength and amount of sample injected. The aggregation onset, as evaluated by the value of the threshold potential, is affected by the charge density of the sample polymer molecules and Debye screening effects and investigated through variation of pH and ionic strength, respectively. Exchange of a simple base buffer component for small and multiply charged organic bases markedly increases the electric field strength necessary to trigger the electrohydrodynamic instabilities. Ultimately, the threshold value could be increased more than seven times by addition of an oppositely charged aminodextran polymer, thereby decreasing the analysis time. © 1999 John Wiley & Sons, Inc. Biopoly 49: 515–524, 1999