Coupling of acetonitrile deproteinization and salting-out extraction with acetonitrile stacking in chiral capillary electrophoresis for the determination of warfarin enantiomers

Min Wang*, Zongwei CAI, Lin Xu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

Concurrent sample clean-up and enhancement in detection sensitivity for chiral capillary electrophoresis was demonstrated based on the coupling of salting-out extraction with acetonitrile stacking and the use of dimethyl-beta-cyclodextrin as the chiral selector for the sensitive and enantioselective separation of warfarin enantiomers in urine samples. By optimizing the pH of salting-out extraction, warfarin enantiomers can be efficiently extracted from the aqueous sample solution into a smaller volume organic solvent (acetonitrile) phase. The pressure injection of the enriched acetonitrile phase (containing ca. 1% NaCl) into the CE capillary at 10% capillary volume resulted in additional concentration of the warfarin enantiomers. The limit of detection for both warfarin enantiomers was as low as 1.5. ng/mL in urine sample. Our results show that the novel strategy offers improved sensitivity compared to conventional CE analysis, reaching a combined enrichment factor higher than 1000. Calibration curves of warfarin enantiomers in urine samples were found to be linear between 10 and 1000. ng/mL, and intra- and inter-day precision (N= 9) for both warfarin enantiomers in terms of migration time and peak area were found to be within the range of 0.1-0.8% and 1.0-6.7%, respectively. The recovery of warfarin enantiomers from urine was ca. 90%.

Original languageEnglish
Pages (from-to)4045-4051
Number of pages7
JournalJournal of Chromatography A
Volume1218
Issue number26
DOIs
Publication statusPublished - 1 Jul 2011

Scopus Subject Areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

User-Defined Keywords

  • Acetonitrile deproteinization
  • Acetonitrile stacking
  • Chiral capillary electrophoresis
  • Salting-out extraction

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