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Scientific article
English

Analysis of selected withanolides in plant extract by capillary electrochromatography and microemulsion electrokinetic chromatography

Contributors

Cherkaoui, Samir; Cahours, Xavier; Veuthey, Jean-Luc

Published in

Electrophoresis, vol. 24, no. 3, p. 336-342

Publication date

2003

Abstract

Microemulsion electrokinetic chromatography (MEEKC) coupled with a diode-array detector was developed for the simultaneous analysis of natural steroidal compounds, withanolides including withaferin A, withacnistin and iochromolide. Optimal resolution was obtained with a microemulsion consisting of 70 mM octane, 800 mM 1-butanol, 100 mM sodium dodecyl sulfate (SDS), and 10 mM phosphate-borate buffer (pH 7) using a fused-silica capillary at 25 kV and 40 degrees C. Since this technique is not compatible with mass spectrometry detection, a capillary electrochromatographic method was developed to separate the investigated withanolides. The effects of mobile phase composition and pH were systematically investigated. Complete separation was obtained with a capillary electrochromatography (CEC) Hypersil C18 bonded silica column (packed length, 25 cmx100 microm ID and 375 microm OD), packed with 3 microm particles. The mobile phase consisted of formic acid-ammonia, pH 8 / acetonitrile (40/60 v/v); the voltage was set at 25 kV and the temperature at 20 degrees C. Under these conditions, resolution of these closely related compounds, including the critical pair withacnistin and iochromolide, was achieved in less than 5 min. The separations by MEEKC and CEC were compared with that obtained by reversed-phase liquid chromatography and showed similar retention order, indicating the analogy of the retention mechanism of these techniques. To further improve specificity and sensitivity, the developed CEC method was interfaced with electrospray ionization mass spectrometry using a Teflon connection between the CEC column and a void fused-silica capillary. Finally, the described methods were applied to the qualitative analysis of withanolides in Iochroma gesnerioides plant extract.

Keywords

  • Chromatography, Micellar Electrokinetic Capillary
  • Ergosterol/analogs & derivatives/isolation & purification
  • Indicators and Reagents
  • Lactones/isolation & purification
  • Plant Extracts/isolation & purification
  • Spectrometry, Mass, Electrospray Ionization
  • Withania/chemistry

UNIGE affiliation entities

Citation (ISO format)

CHERKAOUI, Samir, CAHOURS, Xavier, VEUTHEY, Jean-Luc. Analysis of selected withanolides in plant extract by capillary electrochromatography and microemulsion electrokinetic chromatography. In: Electrophoresis, 2003, vol. 24, n° 3, p. 336–342. doi: 10.1002/elps.200390043

Main files (1)

Article (Published version)

Identifiers

Journal ISSN

0173-0835
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8downloads

Technical informations

Creation

26/03/2010 11:05:00

First validation

26/03/2010 11:05:00

Update

14/03/2023 15:25:52

Status update

14/03/2023 15:25:52

Last indexation

29/10/2024 14:18:42
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