DETERMINATION OF SEVEN ACTIVE INGREDIENTS IN THREE PLANT ESSENTIAL OILS BY USING MICELLAR ELECTROKINETIC CHROMATOGRAPHY

A simple micellar electrokinetic chromatography (MEKC) method was developed for determination of citronellal, citral (Z; E), alpha-pinene, limonene, linalool, and eugenol in plant essential oils (EOs). A buffer consisting of 20mM Na2B4O7, 50mM SDS, 20% (v: v) methanol adjusted to pH 9.5 was found to provide a very efficient and stable electrophoretic system for the analysis. The validation of the method included linearity, LODs, LOQs, precision (intra - and inter - day variation of migration time and peak area), and recovery. Seven terpenoids presented good linearity (R-2 > 0.9960) within the test ranges; LODs (S/N = 3) and LOQs (S/N = 10) were 0.2-1.8 mu g/mL and 0.8-5.9 mu g/mL, respectively. The precision and accuracy were satisfactory, with the overall intra- and inter-day variation (for migration time and peak area, RSD%) being less than 7.0%, and recoveries of this method were greater than 91% at spiked levels. The proposed method was successfully applied to the determination of seven terpenoids in clove oil, litsea cubeba oil, and citronella oil, respectively.