[Determination 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 x 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 x g(-1) and ruscogenin was 0.008 mg x 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.