Electrokinetic stacking injection of neutral analytes under continuous conductivity conditions
Electrokinetic stacking injection of neutral analytes under continuous conductivity conditions
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DOI：
10.1021/ac010522c
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发表时间：
2002-02-01
影响因子：
7.4
通讯作者：
Landers, JP
中科院分区：
文献类型：
--
作者：
Palmer, J;Burgi, DS;Landers, JP
在毛细管电动色谱中，中性分析物可以通过电渗流直接从样品基质注入含有具有相反迁移率的电动载体的分离缓冲液中。分析物以电渗流的速度进样，但作为分析物/胶束复合物保留在样品基质共离子和分离缓冲液胶束区的界面处。一个简单的电动色谱系统，含有十二烷基硫酸钠作为胶束剂与硼酸盐作为缓冲电解质，包括在分离缓冲液和样品基质，以提供连续的电导率进行了研究。探讨了胶束、甲醇和硼酸盐在分离缓冲液中的浓度，以增加中性分析物的最大进样长度。在从样品瓶注射期间，降低分离缓冲液中的分析物速度而基本上不降低分析物的速度允许极大地延长样品塞注射长度。目前可以用50 μ m-i. d进样相当于7个有效毛细管长度（180 cm）的样品溶剂体积。毛细管（有效毛细管长度为24.5 cm），进样总体积约为3.5穆尔，介绍了电动毛细管色谱中这种堆积模式的进样过程方程和最大进样长度。这项工作的结果导致一个假设的概括电动堆积注射最大值电泳过程中，正交分析物堆积/注射系统的概念进行了讨论。
In capillary electrokinetic chromatography, neutral analytes can be injected by electroosmotic flow directly from a sample matrix into a separation buffer containing an electrokinetic vector with an opposite mobility. Analytes are injected at the velocity of electroosmotic flow but are retained at the interface of the sample matrix co-ion and separation buffer micelle zones as analyte/micelle complexes. A simple electrokinetic chromatography system containing sodium dodecyl sulfate as the micellar agent with borate as the buffering electrolyte included in the separation buffer and in the sample matrix to provide continuous conductivity was investigated. Concentrations of the micelle, methanol, and borate in the separation buffer were explored to increase maximum injection length of neutral analytes. Reducing the analyte velocity in the separation buffer without substantially decreasing the velocity of the analyte during injection from the sample vial allowed greatly extended sample plug injection lengths. It is presently possible to inject sample solvent volumes equivalent to similar to7 effective capillary lengths (180 cm) with a 50-mum-i.d. capillary (24.5 cm effective capillary length), total volume of sample injection similar to3.5 muL Equations describing the injection process and maximum injection lengths for this mode of stacking in electrokinetic capillary chromatography are introduced. The result of this work leads to a postulated generalization of electrokinetic stacking injection maximums for electrophoretic processes, and the concept of orthogonal analyte stacking/ injection systems is discussed.