Simultaneous detection of Tripterygium wilfordii sesquiterpene alkaloids by microemulsion electrokinetic chromatography coupled with large volume sample stacking

Abstract

A new simple, rapid and sensitive method using microemulsion electrokinetic chromatography (MEEKC) coupled with large volume sample stacking (LVSS) for the detection of five Tripterygium wilfordii sesquiterpene alkaloids (peritassine A, wilforgine, wilfordine, triptonine B and wilforine) was developed in this paper. For the separation of five Tripterygium wilfordii sesquiterpene alkaloids, a running buffer composed of 0.5% (w/v, 17 mmol/L) sodium dodecyl sulfate, 3.0% (v/v) n-butanol, 0.5% (v/v) n-hexane, 3.0% (v/v) ethanol, 7.0% (v/v) acetonitrile and 86.5% (v/v) 5 mmol/L Na2B4O7–10 mmol/L NaH2PO4 buffer (pH 8.5) was used. In order to improve the sensitivity, MEEKC combined with on-line preconcentration of large volume sample stacking was applied. The detection limits (defined as S/N = 3) in the range of 0.003–0.009 μg/mL were feasible. The proposed LVSS-MEKC was successfully applied to the detection of four analytes in Tripterygium wilfordii root bark with the average recoveries ranged from 103.2% to 107.2%.