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Control of electrohydrodynamic distortion of sample streams in continuous flow electrophoresis using oscillating fields
Author(s) -
Heller Christoph,
Limat Laurent,
Sergot Philippe,
Viovy Jean Louis
Publication year - 1993
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.11501401195
Subject(s) - electrohydrodynamics , electrolyte , laminar flow , electrophoresis , field (mathematics) , mechanics , analytical chemistry (journal) , materials science , electric field , distortion (music) , chemistry , electrode , chromatography , optoelectronics , physics , mathematics , quantum mechanics , pure mathematics , amplifier , cmos
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 distorsions which reduce the separation power of this technique. We demonstrate theoretically that the rate of electrohydrodynamic distorsion 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.