Chaisuwan Patcharin, Nacapricha Duangjai, Wilairat Prapin, Jiang Zhengjin, Smith Norman W
Flow Innovation-Research for Science and Technology Laboratories, Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
Electrophoresis. 2008 Jun;29(11):2301-9. doi: 10.1002/elps.200700689.
This work reports the first use of a monolith with method development for the separation of tocopherol (TOH) compounds by CEC with UV detection. A pentaerythritol diacrylate monostearate-ethylene dimethacrylate (PEDAS-EDMA) monolithic column has been investigated for an optimised condition to separate alpha-, beta-, gamma- and delta-TOHs, and alpha-tocopherol acetate (TAc). The PEDAS-EDMA monolith showed a remarkably good selectivity for separation of the TOH isomers including the beta- and gamma-isomers which are not easily separated by standard C8 or C18 particle-packed columns. Retention studies indicated that an RP mechanism was involved in the separation on the PEDAS-EDMA column, but polar interactions with the underlying ester and hydroxyl groups enhanced the separation of the problematic beta- and gamma-isomers. Separation of all the compounds was achieved within 25 min using 3:10:87 v/v/v 100 mM Tris buffer (pH 9.3)/methanol/ACN as the mobile phase. The method was successfully applied to a pharmaceutical sample with recoveries from 93 to 99%. Intraday and interday precisions (%RSD) for peak area and retention time were less than 2.3. LODs for all four TOHs and TAc were below 1 ppm.
本研究首次报道了采用整体柱结合方法开发，通过毛细管电色谱（CEC）与紫外检测联用对生育酚（TOH）化合物进行分离。对季戊四醇二丙烯酸单硬脂酸酯-乙二醇二甲基丙烯酸酯（PEDAS-EDMA）整体柱进行了研究，以优化其分离α-、β-、γ-和δ-生育酚以及α-生育酚乙酸酯（TAc）的条件。PEDAS-EDMA整体柱在分离TOH异构体方面表现出显著的良好选择性，包括标准C8或C18颗粒填充柱难以分离的β-和γ-异构体。保留研究表明，在PEDAS-EDMA柱上的分离涉及反相（RP）机制，但与底层酯基和羟基的极性相互作用增强了有问题的β-和γ-异构体的分离。使用3:10:87 v/v/v的100 mM Tris缓冲液（pH 9.3）/甲醇/乙腈作为流动相，在25分钟内实现了所有化合物的分离。该方法成功应用于一个药物样品，回收率为93%至99%。峰面积和保留时间的日内和日间精密度（%RSD）均小于2.3。所有四种生育酚和TAc的检测限均低于1 ppm。
