Electrophoresis of macromolecules in solution detected by electrophoresis-NMR

Polyelectrolytes are macromolecules with charges bound to the polymer chain. Electrostatic interactions strongly influence polyelectrolyte properties. Pulsed field gradient nuclear magnetic resonance (PFGNMR) is applied to probe dynamic displacements of polyelectrolytes in aqueous solutions. The electrophoretic mobility is measured, and the friction constant for translational motion is calculated from self-diffusion coefficient. Knowledge of both the electrophoretic mobility and friction coefficient allows the effective charge to be determined. The experiment-derived effective charge is compared to theoretical prediction based on counterion condensation. The effect of low molecular-weight salt upon the effective charge is analyzed qualitatively.