Fast enantiomeric separation with vancomycin as chiral additive by co‐electroosmotic flow capillary electrophoresis: Increase of the detection sensitivity by the partial filling technique
Fast enantiomeric separation with vancomycin as chiral additive by co‐electroosmotic flow capillary electrophoresis: Increase of the detection sensitivity by the partial filling technique
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DOI：
10.1002/elps.200305402
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发表时间：
2003-08
期刊：
影响因子：
2.9
通讯作者：
Jingwu Kang;D. Wistuba;V. Schurig
中科院分区：
文献类型：
--
作者：
Jingwu Kang;D. Wistuba;V. Schurig
建立了一种以万古霉素为手性添加剂的毛细管电泳分离对映体的方法。为了克服与在CE中使用万古霉素作为手性添加剂相关的缺点，在该方法中依次采用了几种策略，包括动态涂层技术、共电渗流技术和部分填充技术。用聚阳离子聚合物溴化己二甲铵（HDB）作为缓冲添加剂，动态地将吸附的HDB在毛细管壁上形成一层薄膜。因此，通过毛细管壁涂层和万古霉素分子之间的静电排斥，使万古霉素在毛细管壁上的吸附最小化。此外，由带正电荷的毛细管壁产生的反向电渗流（从阴极到阳极）以与带负电荷的分析物相同的方向迁移（共电渗流电泳）。因此，带负电荷的分析物的电泳迁移率大大加快，导致不到3.4分钟的短分离时间。通过使用短端进样技术，进一步缩短了分离时间。例如，对于丹磺酰-α-氨基-正丁酸的基线分离，分析时间短至55 s。同时，使用部分填充技术来避免由于运行缓冲液中存在万古霉素而导致的检测灵敏度损失。考察了HDB浓度、缓冲液pH值、手性选择剂插塞长度、手性选择剂浓度、外加电压等因素对手性选择性的影响，并进行了优化。该方法除具有分离时间短的优点外，还具有检测灵敏度高、选择性好、效率高等特点。
A fast and sensitive method is described by using vancomycin as a chiral additive for enantiomeric separation by capillary electrophoresis (CE). In order to overcome disadvantages associated with use of vancomycin as chiral additive in CE, several strategies including the dynamic coating technique, the co‐electroosmotic flow technique, and the partial filling technique were employed sequentially in this method. Using the polycationic polymer hexadimethrine bromide (HDB) as a buffer additive, the capillary wall was dynamically coated with a thin film formed by the adsorbed HDB. Consequently, the adsorption of vancomycin onto the capillary wall was minimized via electrostatic repulsion between the coating of the capillary wall and the vancomycin molecule. In addition, the reversed electroosmotic flow (from cathode to anode) produced by the positively charged capillary wall migrates in the same direction of negatively charged analytes (co‐electroosmotic flow electrophoresis). Thereby the electrophoretic mobility of negatively charged analytes were drastically accelerated leading to a short separation time of less than 3.4 min. The separation time was further reduced by the use of a short‐end‐injection technique. For example, the analysis time was achieved by as short as 55 s for a baseline separation of dansyl‐α‐amino‐n‐butyric acid. Concurrently, the partial filling technique was used to avoid the loss of detection sensitivity caused by the presence of vancomycin in the running buffer. The effect of several parameters, such as HDB concentration, buffer pH, plug length of the chiral selector, concentration of the chiral selector and applied voltage, on enantioselectivity were investigated toward optimization. Besides the advantage of a very short separation time, the method is characterized by high detection sensitivity, high selectivity, and high efficiency.