Document Detail

Determination of pKa values by capillary zone electrophoresis with a dynamic coating procedure.
MedLine Citation:
PMID:  16342805     Owner:  NLM     Status:  MEDLINE    
CZE allows to measure the acidic dissociation constant (pKa) of many drug substances. However, determining the EOF intensity may be time-consuming, especially at a low pH. In order to overcome this drawback, a dynamic coating procedure of the capillary was carried out to increase microEOF, and thus to reduce the analysis time. In addition, this coating procedure enhanced migration time stability. The effective mobilities of 15 compounds were measured at different pH, producing pK'a values dependent on BGE ionic strength. The latter values were corrected with the activity coefficient to obtain a "true" pKa value. The 15 investigated compounds were (i) five acids: namely, salicylic acid, benzoic acid, ketoprofen, phenobarbital, and phenol, (ii) four bases: lidocaine, propafenone, propranolol, and quinine, (iii), five ampholytes: sulfanilamide, sulfabenzamide, sulfadimethoxine, sulfadoxine, and sulfisoxazole, and (iv) one zwitterion: cetirizine. The range of determined pKa values was between 1.2 and 11.2, and close to the pKa values available from the literature.
Laurent Geiser; Yveline Henchoz; Alexandra Galland; Pierre-Alain Carrupt; Jean-Luc Veuthey
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of separation science     Volume:  28     ISSN:  1615-9306     ISO Abbreviation:  J Sep Sci     Publication Date:  2005 Nov 
Date Detail:
Created Date:  2005-12-13     Completed Date:  2006-07-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101088554     Medline TA:  J Sep Sci     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  2374-80     Citation Subset:  IM    
Laboratory of Pharmaceutical Analytical Chemistry, School of Pharmaceutical Sciences, EPGL, University of Geneva, Switzerland.
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MeSH Terms
Electrophoresis, Capillary / instrumentation*,  methods*
Hydrogen-Ion Concentration
Molecular Structure
Pharmaceutical Preparations / chemistry*
Potentiometry / methods
Reg. No./Substance:
0/Pharmaceutical Preparations

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