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English

Rapid determination of pK (a) values of 20 amino acids by CZE with UV and capacitively coupled contactless conductivity detections

Contributors

Henchoz, Yveline; Schappler, Julie; Geiser, Laurent; Prat, Josiane; Carrupt, Pierre-Alain; Veuthey, Jean-Luc

Published in

Analytical & bioanalytical chemistry, vol. 389, no. 6, p. 1869-1878

Collection

  • Open Access - Licence nationale Springer

Publication date

2007

Abstract

A rapid and universal capillary zone electrophoresis (CZE) method was developed to determine the dissociation constants (pK (a)) of the 20 standard proteogenic amino acids. Since some amino acids are poorly detected by UV, capacitively coupled contactless conductivity detection (C(4)D) was used as an additional detection mode. The C(4)D coupling proved to be very successful on a conventional CE-UV instrument, neither inducing supplementary analyses nor instrument modification. In order to reduce the analysis time for pK (a) determination, two strategies were applied: (i) a short-end injection to reduce the effective length, and (ii) a dynamic coating procedure to generate a large electroosmotic flow (EOF), even at pH values as low as 1.5. As a result, the analysis time per amino acid was less than 2 h, using 22 optimized buffers covering a pH range from 1.5 to 12.0 at a constant ionic strength of 50 mM. pK (a) values were calculated using an appropriate mathematical model describing the relationship between effective mobility and pH. The obtained pK (a) values were in accordance with the literature.

Keywords

  • Amino Acids/analysis
  • Electric Conductivity
  • Electroosmosis
  • Electrophoresis, Capillary/instrumentation/methods
  • Hydrogen-Ion Concentration
  • Models, Theoretical
  • Osmolar Concentration
  • Reproducibility of Results
  • Spectrophotometry, Ultraviolet/methods
  • Temperature

UNIGE affiliation entities

Citation (ISO format)

HENCHOZ, Yveline et al. Rapid determination of pK (a) values of 20 amino acids by CZE with UV and capacitively coupled contactless conductivity detections. In: Analytical & bioanalytical chemistry, 2007, vol. 389, n° 6, p. 1869–1878. doi: 10.1007/s00216-007-1568-5

Main files (1)

Article (Published version)

Identifiers

Journal ISSN

1618-2642
600views
679downloads

Technical informations

Creation

15/06/2010 13:42:00

First validation

15/06/2010 13:42:00

Update

14/03/2023 15:30:00

Status update

14/03/2023 15:30:00

Last indexation

29/10/2024 15:00:58
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