Electromigration dispersion in a capillary in the presence of electro-osmotic flow.
Electromigration dispersion in a capillary in the presence of electro-osmotic flow.
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DOI：
10.1017/jfm.2012.76
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发表时间：
2012-04-01
影响因子：
3.7
通讯作者：
Chen Z
中科院分区：
文献类型：
--
作者：
Ghosal S;Chen Z
离子在外加电场中的差异迁移是毛细管电泳分离化学物质的基础。浓度峰的轴向扩散限制了分离效率。当样品离子浓度与背景离子浓度相当时，观察到电迁移分散。在这样的条件下，局部电导率在样品区中显著改变，使得电场和离子迁移速度依赖于浓度。由此产生的非线性波表现出类似激波的特征，在某些简化假设下，可以用Burgers方程（72，pg.2047）描述。在本文中，我们考虑更一般的情况下，分离通道的壁可能有一个非零的zeta电位，因此能够维持一个电渗透体流。主要结果是一维非线性对流扩散方程的面积平均浓度。该均匀化方程解释了由电渗滑移速度沿着壁的变化引起的泰勒-阿里斯分散。结果表明，在一定的参数范围内，电渗流实际上可以通过延迟浓度冲击的形成来减少总分散。然而，如果电渗流足够高，则由于Taylor-Aris贡献，总分散增加。
The differential migration of ions in an applied electric field is the basis for separation of chemical species by capillary electrophoresis. Axial diffusion of the concentration peak limits the separation efficiency. Electromigration dispersion is observed when the concentration of sample ions is comparable to that of the background ions. Under such conditions, the local electrical conductivity is significantly altered in the sample zone making the electric field, and therefore, the ion migration velocity concentration dependent. The resulting nonlinear wave exhibits shock like features, and, under certain simplifying assumptions, is described by Burgers’ equation ( 72, pg. 2047). In this paper, we consider the more general situation where the walls of the separation channel may have a non-zero zeta potential and are therefore able to sustain an electro-osmotic bulk flow. The main result is a one dimensional nonlinear advection diffusion equation for the area averaged concentration. This homogenized equation accounts for the Taylor-Aris dispersion resulting from the variation in the electro-osmotic slip velocity along the wall. It is shown that in a certain range of parameters, the electro-osmotic flow can actually reduce the total dispersion by delaying the formation of a concentration shock. However, if the electro-osmotic flow is sufficiently high, the total dispersion is increased because of the Taylor-Aris contribution.
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影响因子：
27.7
作者：
MELCHER, JR;TAYLOR, GI
通讯作者：
TAYLOR, GI
DOI：
10.1098/rspa.1956.0065
发表时间：
1956-01-01
影响因子：
--
作者：
ARIS, R
通讯作者：
ARIS, R
影响因子：
4.6
作者：
Rica, Raul A.;Bazant, Martin Z.
通讯作者：
Bazant, Martin Z.
影响因子：
2.9
作者：
Bousková, E;Presutti, C;Bocek, P
通讯作者：
Bocek, P
影响因子：
7.4
作者：
Ghosal, S
通讯作者：
Ghosal, S