Heller C, Limat L, Sergot P, Viovy J L
Laboratoire de Physico-Chimie Théorique, URA CNRS 1382, Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris.
Electrophoresis. 1993 Dec;14(12):1278-83. doi: 10.1002/elps.11501401195.
Continuous flow electrophoresis is a method to separate ions contained in a sample continuously injected into a laminar flow of electrolyte as a cylindrical stream. Usually, the sample is more conductive than the electrolyte, and the charges created at the sample-electrolyte interface lead to electrohydrodynamic distortions which reduce the separation power of this technique. We demonstrate theoretically that the rate of electrohydrodynamic distortion of a cylindrical sample stream can be reduced to zero, by superimposing to the AC field responsible for the separation of a DC field transverse to it and to the flow direction, with an appropriate frequency, and an effective strength equal to that of the DC field. Using a continuous flow electrophoresis chamber, in which such a field is produced using capacitive electrodes, the major predictions of the theory are confirmed. In particular, it is shown that a sample stream more conductive than the carrying electrolyte, which was seriously deformed in the absence of a transverse AC field, recovers its cylindrical shape in presence of the field. The implications of this discovery for the separating power of continuous-flow electrophoresis are discussed.
连续流动电泳是一种将连续注入层流电解质中的样品以圆柱流形式所含离子进行分离的方法。通常，样品的导电性比电解质强，样品 - 电解质界面处产生的电荷会导致电流体动力学畸变，从而降低该技术的分离能力。我们从理论上证明，通过将与负责分离的交流场叠加一个垂直于交流场且与流动方向垂直的直流场，以适当的频率和与直流场强度相等的有效强度，可以将圆柱状样品流的电流体动力学畸变率降低到零。使用一个连续流动电泳室，其中通过电容电极产生这样的场，该理论的主要预测得到了证实。特别是，结果表明，比携带电解质导电性更强的样品流，在没有横向交流场时严重变形，而在有该场时恢复其圆柱形状。讨论了这一发现对连续流动电泳分离能力的影响。
