  We present mesoscopic DPD-simulations of polyelectrolyte electrophoresis in
confined nanogeometries, for varying salt concentration and surface slip
conditions. Special attention is given to the influence of electroosmotic flow
(EOF) on the migration of the polyelectrolyte. The effective polyelectrolyte
mobility is found to depend strongly on the boundary properties, i.e., the slip
length and the width of the electric double layer. Analytic expressions for the
electroosmotic mobility and the total mobility are derived which are in good
agreement with the numerical results. The relevant quantity characterizing the
effect of slippage is found to be the dimensionless quantity $\kappa \:
\delta_B$, where $\delta_B$ is the slip length, and $\kappa^{-1}$ an effective
electrostatic screening length at the channel boundaries.
