Dutta Debashis
Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, USA.
Electrophoresis. 2007 Dec;28(24):4552-60. doi: 10.1002/elps.200700013.
In this article, we present an analysis on the transport of charged samples through micro- and nanofluidic channels with large zeta potentials (|zeta| > (kBT)/e). Using the Method of Moments formulation, the diffusion-convection equation has been solved to evaluate the mean velocity and the dispersion of analyte bands in a parallel-plate device under electrokinetically- and pressure-driven flow conditions. The effect of electromigration induced by the lateral electric field within the Debye layer has been quantified in our work using a Peclet number (Pe t) based on the characteristic electrophoretic velocity of the solute molecules in the transverse direction. It has been shown that while the effects of transverse electromigration on analyte transport only depends on the product Pe t zeta* for |zeta*| = (ezeta)/kBT << 1, both these parameters independently affect the flow of charged species in large zeta potential systems. For a given value of Pe t zeta*, the mean velocity and the slug dispersivity can vary by as much as an order of magnitude in going from a small zeta potential system (|zeta*| << 1) to a channel with |zeta*| = 4.
在本文中，我们对带电荷样品在具有大zeta电位（|zeta| > (kBT)/e）的微纳流体通道中的传输进行了分析。使用矩量法公式，求解了扩散对流方程，以评估在电动和压力驱动流动条件下平行板装置中分析物带的平均速度和分散情况。在我们的工作中，基于溶质分子在横向方向上的特征电泳速度，使用佩克莱数（Pe t）对德拜层内横向电场引起的电迁移效应进行了量化。结果表明，虽然横向电迁移对分析物传输的影响仅取决于|zeta*| = (ezeta)/kBT << 1时的乘积Pe t zeta*，但在大zeta电位系统中，这两个参数均独立影响带电物种的流动。对于给定的Pe t zeta值，从低zeta电位系统（|zeta| << 1）到|zeta*| = 4的通道，平均速度和段塞分散度的变化幅度可达一个数量级。
