Capillary electrophoretic separation of proteins and peptides by ion-pairing with heptanesulfonic acid

I. Mikšík, J. Charvátová, A. Eckhardt, T. Cserháti, E. Forgács, Z. Deyl

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Heptanesulfonic acid as ion-pairing agent was used for the separation of mixtures of low and high molecular mass peptides/proteins by capillary electrophoresis. The separation conditions used were: capillary 37cm (30cm to the detector)×75μm i.d., voltage 10kV, phosphate buffer 50mmol/l, ion-pairing agent heptanesulfonic acid at three different concentrations, namely, 0, 20 or 100mmol/l, pH 2.5. The separation reflected the ion-pairing equilibria between the ion-pairing agent and the peptide/protein analytes. The influence of ion-pairing on sample mobility (running time) was more pronounced in case of the higher-molecular peptides as compared to the low molecular ones. This difference offers the possibility to separate low and high molecular peptides/proteins that under the absence of the ion-pairing agent would co-migrate. The principle of this approach was demonstrated on a randomly selected set of peptides/proteins; the practical applicability was demonstrated on a set of CNBr peptides arising from a naturally occurring mixture of collagen types I and III.

Original languageEnglish
Pages (from-to)161-167
Number of pages7
JournalJournal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
Issue number1-2
Publication statusPublished - Feb 5 2004



  • Heptanesulfonic acid
  • Ion-pairing reagents
  • Peptides
  • Proteins

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry
  • Cell Biology

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