毛细管电泳-电致化学发光法分离测定麻黄中的麻黄碱、伪麻黄碱与甲基麻黄碱

以PB-Eu化学修饰电极为工作电极,对乙烯基苄基三乙基氯化铵离子液体为拆分添加剂,首次采用毛细管电泳-电致化学发光法对麻黄碱、伪麻黄碱和甲基麻黄碱进行了分离和检测。考察了检测电位、分离缓冲液的种类和酸度、添加剂用量等条件对电泳分离效果及检测灵敏度的影响。在优化条件下,3种混合药物可在8 min内达到基线分离,甲基麻黄碱、麻黄碱和伪麻黄碱的质量浓度分别在0.025～10、0.025～25、0.05～10 mg/L范围内与其峰面积呈良好但斜率略不同的两区段型线性关系,总的线性响应范围可达3个数量级。以质量浓度均为1.00 mg/L的3种混合药物合成样品进行6次平行测试,其峰面积和迁移时间的RSD分别小于4.5%和0.95%。该方法成功用于商品麻黄碱类药物制剂及中药麻黄原药中3种生物碱含量的测定,加标回收率为101%～111%。

Separation and Determination of Ephedrine,Pseudoephedrine and Methylephedrine by Capillary Electrophoresis with Electrochemiluminescence Detection

Using an ionic liquid of p-vinylbenzyltriethylammonium chloride as separating additive,a novel method for the simultaneous determination of methylephedrine(ME),ephedrine(E) and pseudoephedrine(PE) was developed by capillary electrophoresis coupled with electrochemiluminescence detection using PB-Eu chemically modified electrode as working electrode.The effect factors,such as detection potential,types and acidity of separation buffer on the separation efficiency were investigated.Under the optimized conditions,three analytes were separated well in 8 min.Good relationships(r2≥0.999 1) between peak area and concentrations of analytes(ME:0.025-10 mg/L,E:0.025-25 mg/L,PE:0.05-10 mg/L) were established over three orders of magnitude.The synthetic samples containing three alkaloids in a level of 1.00 mg/L were determined.The RSDs of peak area and migration time were less than 4.5% and 0.95%,respectively.The method was successfully used in the determination of the three alkaloids in pharmaceutical preparations and Chinese herbal Ma-Huang with recoveries of 101%-111%.