Determination of strychnine and brucine in Strychnos nux-vomica L. by nonaqueous capillary electrophoresis

A nonaqueous capillary electrophoresis method with photo diode-array detection was developed for the analysis of strychnine and brucine in Strychnos nux-vomica L. The separation of the two alkaloids was optimized with respect to the concentration of Tris-boric acid, the proportion of methanol and acetonitrile, and applied voltage. Baseline separation was obtained for the two analytes within 10 min using a running buffer containing 25 mM Tris-boric acid, 60% methanol and 20% acetonitrile with acetic acid adjusting pH to 4.0. In this paper, the method was used to determine the contents of strychnine and brucine in raw material and prepared Strychnos nux-vomica L.