On-line preconcentration and chiral separation of propiconazole by cyclodextrin-modified micellar electrokinetic chromatography

J Chromatogr A. 2007 Nov 2;1170(1-2):107-13. doi: 10.1016/j.chroma.2007.09.003. Epub 2007 Sep 12.

Abstract

A method for the chiral separation of propiconazole using cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) with hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as chiral selector is reported. The use of a mixture of 30 mM HP-gamma-CD, 50mM SDS, methanol-acetonitrile 10%:5% (v/v) in 25 mM phosphate buffer solution was able to separate two enantiomeric pairs of propiconazole. Stacking- and sweeping-CD-MEKC under neutral pH (pH 7) and under acidic condition (pH 3.0) were used as two on-line preconcentration methods to increase detection sensitivity of propiconazole. Good repeatabilities in the migration time, peak area and peak height were obtained in terms of relative standard deviation (RSD). A sensitivity enhancement factor of 100-fold was achieved using sweeping-CD-MEKC at acidic pH. This is the first report on the separation of two pairs of propiconazole enantiomers and all the enantiomers of fenbuconazole and tebuconazole using sweeping-CD-MEKC. The limit of detection (S/N=3) for the three triazole fungicides ranged from 0.09 to 0.1 microg/mL, which is well below the maximum residue limits (MRL) set by Codex Alimentarius Commission (CAC). Combination of solid-phase extraction (SPE) pretreatment and sweeping-CD-MEKC procedure was applied to the determination of selected triazole fungicides in grapes samples spiked at concentration 10-40 times lower than the MRL established by the CAC. The average recoveries of the selected fungicides in spiked grapes samples were good, ranging from 73% to 109% with RSD of 9-12% (n=3).

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Micellar Electrokinetic Capillary / methods*
  • Cyclodextrins / chemistry*
  • Fungicides, Industrial / analysis
  • Hydrogen-Ion Concentration
  • Nitriles / analysis
  • Online Systems*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Sodium Dodecyl Sulfate / chemistry
  • Solid Phase Extraction / methods
  • Stereoisomerism
  • Triazoles / analysis*
  • Triazoles / chemistry
  • Vitis / chemistry
  • Vitis / poisoning*
  • gamma-Cyclodextrins / chemistry*

Substances

  • Cyclodextrins
  • Fungicides, Industrial
  • Nitriles
  • Triazoles
  • gamma-Cyclodextrins
  • hydroxypropyl-gamma-cyclodextrin
  • propiconazole
  • Sodium Dodecyl Sulfate
  • tebuconazole
  • fenbuconazole