Wan H, Blomberg L G, Hamberg M
Department of Chemistry, Karlstad University, Sweden.
Electrophoresis. 1999 Jan;20(1):132-7. doi: 10.1002/(SICI)1522-2683(19990101)20:1<132::AID-ELPS132>3.0.CO;2-I.
A capillary electrophoresis (CE) method has been developed for simple and direct separation of cis- and trans-12,13-epoxy-9(Z)-octadecenoic acid and 9,10-epoxy-12(Z)-octadecenoic acid isomers. Separation was performed in micellar electrokinetic capillary chromatography (MEKC) using a buffer consisting of 25 mM borate (pH 9.20), 10 mM sodium dodecyl sulfate (SDS) and 10% v/v acetonitrile. The key variables, concentrations of SDS and organic modifier, were optimized by the application of a factorial experimental design. The use of a low micellar concentration, just above critical micelle concentration (CMC), in a background electrolyte containing an organic modifier not only made it possible to dissolve and separate highly hydrophobic fatty acid isomers, but also resulted in improved separation efficiency and selectivity. Separation efficiency up to 4 x 10(5) theoretical plates/m was achieved under an optimized condition. Also investigated were the influence of temperature on separation and the effect of organic modifier concentration on the dynamic exchange of the analytes between micelles and the bulk of the buffer solution. Direct UV was applied for detection of the fatty acids.
已开发出一种毛细管电泳（CE）方法，用于简单直接地分离顺式和反式-12,13-环氧-9（Z）-十八碳烯酸以及9,10-环氧-12（Z）-十八碳烯酸异构体。分离在胶束电动毛细管色谱（MEKC）中进行，使用由25 mM硼酸盐（pH 9.20）、10 mM十二烷基硫酸钠（SDS）和10% v/v乙腈组成的缓冲液。通过应用析因实验设计对关键变量SDS和有机改性剂的浓度进行了优化。在含有有机改性剂的背景电解质中使用略高于临界胶束浓度（CMC）的低胶束浓度，不仅能够溶解和分离高度疏水的脂肪酸异构体，还提高了分离效率和选择性。在优化条件下实现了高达4×10⁵理论塔板数/米的分离效率。还研究了温度对分离的影响以及有机改性剂浓度对分析物在胶束和缓冲液主体之间动态交换的影响。采用直接紫外检测脂肪酸。
