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Determination of cationic mobilities and p K a values of 22 amino acids by capillary zone electrophoresis
Author(s) -
Včeláková Kateřina,
Zusková Iva,
Kenndler Ernst,
Gaš Bohuslav
Publication year - 2004
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305751
Subject(s) - capillary electrophoresis , electrolyte , cationic polymerization , chemistry , dissociation (chemistry) , ionic bonding , dissociation constant , limiting , analytical chemistry (journal) , ionic strength , electrophoresis , conductivity , ionic conductivity , thermodynamics , chromatography , aqueous solution , ion , organic chemistry , physics , mechanical engineering , biochemistry , receptor , electrode , engineering
The effective mobilities of the cationic forms of common amino acids – mostly proteinogenic – were determined by capillary zone electrophoresis in acidic background electrolytes at pH between 2.0 and 3.2. The underivatized amino acids were detected by the double contactless conductivity detector. Experimentally measured effective mobilities were fitted with the suitable regression functions in dependence on pH of the background electrolyte. The parameters of the given regression function corresponded to the values of the actual mobilities and the mixed dissociation constants (combining activities and concentrations) of the compound related to the actual ionic strength. McInnes approximation and Onsager theory were used to obtain thermodynamic dissociation constants (p K a ) and limiting (absolute) ionic mobilities.