Hou Jingguo, Zheng Jie, Rizvi Syed A A, Shamsi Shahab A
Department of Chemistry, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, USA.
Electrophoresis. 2007 May;28(9):1352-63. doi: 10.1002/elps.200600415.
In this work, simultaneous separation of eight stereoisomers of ephedrine and related compounds ((+/-)-ephedrine, (+/-)-pseudoephedrine, (+/-)-norephedrine and (+/-)-N-methylephedrine) was accomplished using a polymeric chiral surfactant, i.e. polysodium N-undecenoxycarbonyl-L-leucinate (poly-L-SUCL) by chiral (C)MEKC-ESI-MS. The conditions of CMEKC were first investigated. The baseline separation of all eight stereoisomers of ephedrine and related compounds was achieved under optimum CMEKC conditions (35 mM poly-L-SUCL, 15 mM NH(4)OAc, pH 6.0, 30% v/v ACN, 30 kV and 20 degrees C) in less than 30 min. Next, a central composite design for response surface modeling has been described to evaluate the electrospray chamber parameters and the sheath liquid conditions. Optimum mass abundance of stereoisomers of ephedrine and related compounds was observed using the spray chamber parameters, namely 250 degrees C drying gas temperature and 8 L/min drying gas flow rate at a nebulizer pressure of 4 psi. Furthermore, the experimental design indicates that the optimum mass abundance of the stereoisomers of ephedrine and related compounds can be obtained using a sheath liquid containing 80:20 v/v methanol-water, 5 mM NH(4)OAc at pH 8.5 delivered at 5 microL/min. Finally, compared to MEKC-UV, the use of poly-L-SUCL in MEKC-MS provided significantly higher sensitivity for stereoisomers of ephedrine and related compounds.
在本研究中，使用一种聚合手性表面活性剂，即N-十一碳烯氧基羰基-L-亮氨酸多钠盐（聚-L-SUCL），通过手性毛细管胶束电动色谱-电喷雾电离质谱法（C）MEKC-ESI-MS，实现了麻黄碱及其相关化合物（（±）-麻黄碱、（±）-伪麻黄碱、（±）-去甲麻黄碱和（±）-N-甲基麻黄碱）的8种立体异构体的同时分离。首先研究了CMEKC的条件。在最佳CMEKC条件（35 mM聚-L-SUCL、15 mM醋酸铵、pH 6.0、30% v/v乙腈、30 kV和20℃）下，不到30分钟就实现了麻黄碱及其相关化合物的所有8种立体异构体的基线分离。接下来，描述了一种用于响应面建模的中心复合设计，以评估电喷雾室参数和鞘液条件。在喷雾室参数为250℃干燥气体温度、8 L/min干燥气体流速、雾化器压力为4 psi的条件下，观察到麻黄碱及其相关化合物立体异构体的最佳质量丰度。此外，实验设计表明，使用含有80:20 v/v甲醇-水、5 mM醋酸铵、pH 8.5、流速为5 μL/min的鞘液，可以获得麻黄碱及其相关化合物立体异构体的最佳质量丰度。最后，与MEKC-UV相比，在MEKC-MS中使用聚-L-SUCL对麻黄碱及其相关化合物的立体异构体具有显著更高的灵敏度。
