Separation and analysis of the major constituents of cloves by micellar electrokinetic chromatography

A micellar electrokinetic chromatographic method was developed for the first time and applied to the separation and quantification of the main components of cloves, namely eugenol and beta-caryophyllene. The analytes were separated in less than ten minutes in an unmodified fused silica capillary (effective length: 40.0 cm) using a background electrolyte composed of 25 mM carbonate buffer (pH 10.0) and 60 mM sodium dodecylsulfate. Analyte concentrations were determined in clove oil and in methanolic clove extracts after simple sequential dilution with methanol and background electrolyte, and the resulting electropherograms showed no interference due to other components. Precision and accuracy assays gave satisfactory results, with mean standard deviation lower than 2.5% (lower than 1.5% for migration times) and mean recovery higher than 98%. The eugenol content of a commercial clove oil was about 70% (RSD = 3.2%), while that of β-caryophyllene was about 15% (RSD = 4.2%); in clove extracts, on the other hand, eugenol was approximately 15% (RSD = 4.7%) and β-caryophyllene 4% (RSD = 5.1%).