etermination of diosgenin and ruscogenin in Radix Ophiopogonis by nonaqueous capillary electrophoresis

Nonaqueous capillary electrophoresis is used for the determination of the contents of diosgenin and ruscogenin in Radix Ophiopogonis.  The operating buffer was composed of 20 mmol·L⁻¹ Na₂B₄O₇-HCl (pH 7.61) in 70% methanol.  The applied voltage was 25 kV and detection potential was at +0.70 V.  With these conditions, the components were successfully separated.  The content of diosgenin in Radix Ophiopogonis was 0.018 mg·g⁻¹ and ruscogenin was 0.008 mg·g⁻¹.  The average recoveries of diosgenin and ruscogenin were 102% and 99.2%, respectively.  A new method of the quality control of diosgenin and ruscogenin in Radix Ophiopogonis is provided.