毛细管区带电泳法测定麻黄及麻杏石甘汤中麻黄碱和伪麻黄碱的含量

目的:采用毛细管区带电泳法测定麻黄及麻杏石甘汤中麻黄碱和伪麻黄碱.方法:电泳缓冲液为50 mmol·L~(-1)硼砂/20 mmol·L~(-1)苏氨酸缓冲溶液(1 mol·L~(-1) NaOH溶液调pH至9.27);紫外检测波长210 nm,分离电压15 kV;以苯巴比妥为内标物,采用压力进样(10 cm×20 s),柱温室温.结果:麻黄碱与伪麻黄碱的线性范围分别为21.3～213,8.4～84 mg·L~(-1),相关系数分别为0.999 6,0.999 5,检测限分别为1.45,1.48 mg·L~(-1),定量限分别为4.81,4.93 mg·L~(-1).将该法用于麻黄中麻黄碱与伪麻黄碱的含量测定,平均回收率分别为97.5,98.6%.结论:本法操作简便、快速、经济、灵敏度高,麻黄及麻杏石甘汤中麻黄碱及伪麻黄碱可获得满意的分离,可作为麻黄和麻杏石甘汤中麻黄碱和伪麻黄碱的含量测定方法.

Determination of ephedrine and pseudoephedrine in Herba Ephedrae and Maxing Shigan Tang by capillary zone electrophoresis

Objective: To establish a method for the determination of ephedrine and pseudoephedrine in Herba Ephedrae and Maxing Shigan Tang by capillary zone electrophoresis.  Method: The conditions of the experiment were optimized with a fused-silica capillary of 60 cm×50 μm (50 cm effective length) in a running buffer of 50 mmol·L-1 borax-20 mmol·L-1 threonine (pH 9.27) and an applied voltage of 15 kV (room temperature). Samples were introduced by hydrodynamic injections (10 cm×20 s)and determined with on-column UV monitoring at 210 nm. Phenobarbital was chosen as the internal standard.  Result: Ephedrine and pseudoephedrine are separated successfully within 8 min. The linear responses covered the ranges from 21.3 to 213 mg·L-1 (r=0.999 6) for ephedrine and from 8.4 to 84 mg·L-1 (r=0.999 5) for pseudoephedrine. The detection limits (S/N=3) of ephedrine and pseudoephedrine were shown to be 1.45 and 1.48 μg·mL-1, respectively, The quantitation limits (S/N=10) of ephedrine and pseudoephedrine were shown to be 4.81 and 4.93 mg·L-1, respectively. The average recoveries for ephedrine and pseudoephedrine were 97.5% and 98.6% with RSD less than 5.0%.  Conclusion: The method is simple, rapid, cost-effective and precise with satisfactory results.