SPONTANEOUS INJECTION IN MICROCOLUMN SEPARATIONS
SPONTANEOUS INJECTION IN MICROCOLUMN SEPARATIONS
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DOI：
10.1021/ac00086a018
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发表时间：
1994-07-15
影响因子：
7.4
通讯作者：
ZARE, RN
中科院分区：
文献类型：
--
作者：
FISHMAN, HA;AMUDI, NM;ZARE, RN
研究了微柱分离中的自发进样现象，以提高超微量进样的定量精度和分离效率。通过结合荧光成像、视频显微镜和毛细管电泳法的测量，我们证明自发注入主要是由毛细管入口处形成的界面压力差引起的。基于流体动力学的一些简单假设对这种复杂的注入机理进行了建模。特别是，研究表明，通过蚀刻毛细管入口或使用薄壁毛细管，外来注射最多可减少12倍。如果不能精确控制时间，样品引入和重新插入进瓶之间的延迟可能会导致进样长度相差2倍。有证据表明，从进口蒸发缓冲液可以使喷射长度缩短1个数量级以上。
The phenomenon of spontaneous (ubiquitous) injection in microcolumn separations has been characterized to improve quantitative precision for ultramicrosampling and to enhance separation efficiency. By combining fluorescence imaging, video microscopy, and measurements from capillary electrophoresis, we demonstrate that spontaneous injection is caused primarily by an interfacial pressure difference formed at the inlet of the capillary. This complex injection mechanism has been modeled with some simple assumptions based on fluid dynamics. In particular, studies showed that extraneous injection is reduced up to 12-fold by etching the capillary inlet or by using a thin-walled capillary. Variations by a factor of 2 in the injection length can result from delays between sample introduction and reinsertion into the inlet vial if the timing is not controlled precisely. Evidence is presented that evaporation of buffer from the inlet can reduce the injection length by more than 1 order of magnitude.