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Updated: Jun 28, 2026

On-chip Isotachophoresis for Separation of Ions and Purification of Nucleic Acids
Published on: March 2, 2012
Salt-induced counterion-mobility anomaly in polyelectrolyte electrophoresis
Sebastian Fischer1, Ali Naji, Roland R Netz
1Physik Department, Technische Universität München, Garching, Germany.
Abstract:
We study the electrokinetics of a single polyelectrolyte chain in salt solution using hydrodynamic simulations. The salt-dependent chain mobility compares well with experimental DNA data. The mobility of condensed counterions exhibits a salt-dependent change of sign, an anomaly that is also reflected in the counterion excess conductivity. Using Green's function techniques this anomaly is explained by electrostatic screening of the hydrodynamic interactions between the chain and counterions.
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