Journal
JOURNAL OF CHROMATOGRAPHY A
Volume 1051, Issue 1-2, Pages 283-290Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.chroma.2004.08.069
Keywords
pK(a); determination; quinolones; antibiotics; capillary zone electrophoresis
Ask authors/readers for more resources
Electrophoretic behavior and pK(a) determination of six quinolones with a piperazinyl substituent, together with two quinolones without a piperazinyl substituent and 1-phenylpiperazine, were investigated by capillary zone electrophoresis. The results indicate that quinolones with a piperazinyl substituent involve three protonation/deprotonation equilibria. The results also suggest that the contribution of the zwitterionic species of these quinolones to the effective mobility may not be neglected. This is probably due to a slightly incomplete protonation of the piperazinyl moiety in the pH range of 6.0-8.0, compared with the complete dissociation of the carboxylic group. Consequently, the zwitterionic species of ciprofloxacin, in particular, is slightly negatively charged. With the aid of computer simulation, three pKa values were determined for quinolones with a piperazinyl substituent, thus allowing us to rationalize precisely the influence of pH on the electrophoretic behavior of these compounds. (C) 2004 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available