Characterization of gold nanoparticles with different hydrophilic coatings via capillary electrophoresis and Taylor dispersion analysis. Part I: Determination of the zeta potential employing a modified analytic approximation. - Pyell, Ute; Jalil, Alaa H.; Pfeiffer, Christian; Pelaz, Beatriz; Parak, Wolfgang J. (Journal of Colloid & Interface Science, 2015)