Field-amplified sample stacking in capillary electrophoresis for the determination of alkaloids in Sinomenium acutum

Abstract

An easy, rapid method for the simultaneous determination of isotetrandrine, curine, sinactine, sinomenine and magnoflorine in Sinomenium acutum was developed by a capillary electrophoresis (CE) method with field-amplified sample stacking (FASS). Parameters affecting CE separation and FASS performance were all carefully investigated to obtain the best sensitivity with the highest speed. Under the optimized conditions: UV detection at 214 nm, separation voltage 25 kV, 40 mM sodium citrate–citric acid (pH 3.5) as running buffer, the detection sensitivity was from 4.8 × 10⁻⁹ M to 1.0 × 10⁻⁸ M. This resulted in 20–100-fold improvement in concentration sensitivity relative to conventional capillary electrophoresis methods. The relative standard deviation (RSD) of the peak area ratios for repeatability (intraday, n = 5) and intermediate precision (interday, n = 5) were lower than 4.1% and 5.4%, respectively. Finally, the developed method was successfully applied to qualitatively and quantitatively analyze five alkaloids in Sinomenium acutum, with the recovery ranging from 75.5 to 102.2%.