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Electroosmotic flow changes due to interactions of background electrolyte counter‐ions with polyethyleneimine coating in capillary zone electrophoresis of proteins
Author(s) -
Spanilá Miroslava,
Pazourek Jiří,
Havel Josef
Publication year - 2006
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200500461
Subject(s) - electrolyte , capillary electrophoresis , chemistry , electrophoresis , capillary electrochromatography , chromatography , capillary action , tartrate , coating , ionic strength , malonate , electro osmosis , analytical chemistry (journal) , inorganic chemistry , organic chemistry , materials science , aqueous solution , electrode , composite material
The properties and behavior of polyethyleneimine (PEI) covalently coated capillaries with respect to different background electrolytes used in capillary zone electrophoresis (CZE) are described. The coating stability and changes of inner surface charge in the capillary were followed by measurement of electroosmotic flow (EOF). Interest was focused mainly on conjugate bases of carboxylic acids as anionic background electrolyte components (acetate, citrate, malate, malonate, tartrate, and succinate). An interesting phenomenon was observed in PEI‐coated capillaries: The direction (and the magnitude) of EOF depends on the composition of the background electrolyte and at a certain pH it can undergo reversible change. Ionic complex formation was suggested as a hypothesis to explain this behavior. With this knowledge, the PEI‐coated capillary was used for the separation of basic proteins in the above‐mentioned background electrolytes. A standard protein mixture of cytochrome c, ribonuclease A, and lysozyme at a concentration of 0.25 mg/mL each was chosen as model sample.