Capillary electrophoresis of clenbuterol enantiomers and NMR investigation of the clenbuterol/carboxymethyl-β-cyclodextrin complex

J Chromatogr Sci. 2013 Mar;51(3):237-41. doi: 10.1093/chromsci/bms133. Epub 2012 Sep 17.


A capillary electrophoretic method has been established for the separation of the enantiomers of clenbuterol. The effects of pH value, composition of the background electrolyte, concentration of carboxymethyl-β-cyclodextrin (CM-β-CD), capillary temperature and running voltage have been investigated. The two enantiomers were separated in an uncoated capillary with phosphate buffer (50 mmol/L, pH 3.5) containing 10 mmol/L CM-β-CD. The capillary temperature was at 15°C and applied voltage was at 20 kV. The inclusion complex of CM-β-CD and clenbuterol was synthesized and characterized by two-dimensional rotating frame spectroscopy (2D ROESY). Based on the 2D ROESY analysis, an inclusion structure of the clenbuterol/CM-β-CD complex was proposed, in which clenbuterol penetrated CM-β-CD in a tilted manner due to the interaction of intermolecular hydrogen bonds between clenbuterol and CM-β-CD.

MeSH terms

  • Chromatography, High Pressure Liquid
  • Chromatography, Thin Layer
  • Clenbuterol / chemistry*
  • Clenbuterol / isolation & purification*
  • Electrophoresis, Capillary / methods*
  • Limit of Detection
  • Linear Models
  • Magnetic Resonance Spectroscopy / methods*
  • Reproducibility of Results
  • Stereoisomerism
  • beta-Cyclodextrins / chemistry*


  • beta-Cyclodextrins
  • carboxymethyl-beta-cyclodextrin
  • Clenbuterol