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

KeyWord:capillary electrophoresis  electrochemiluminescence  ionic liquid  alkaloid

Abstract:

      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¡Ý0.999 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%.