title: Characterization of hydrophilic coated gold nanoparticles via capillary electrophoresis and Taylor dispersion analysis. Part II: Determination of the hydrodynamic radius distribution - Comparison with asymmetric flow field-flow fractionation.
abstract: In the first paper of this series we have shown for hydrophilic coated Au nanoparticles that capillary electrophoresis in combination with Taylor dispersion analysis in fused silica capillaries with an inner diameter of 75 μm allows for the unbiased precise determination of the number-weighted mean hydrodynamic diameter, the zeta potential and the effective charge number, although mobility corrected double layer polarization has to be taken into account. In this second paper we investigate whether the modified approximate analytic expression developed by Ohshima (2001) permits the calculation of calibration lines and the concomitant conversion of electropherograms into number-weighted particle radius distributions. We show that with the method developed size distributions are obtained which are independent of the measurement conditions. These size distributions are much narrower than those obtained via dynamic light scattering and data evaluation by the CONTIN algorithm. Capillary electrophoresis together with the proposed data evaluation method reveals that the analyzed nanoparticle populations have very narrow size distributions with a width of 2-4 nm. The hydrodynamic radius distributions of the coated NPs are only slightly broader than the solid particle radius distribution of the Au-NP cores. The presence of monomodal/bimodal size distributions is confirmed by asymmetric flow field-flow fractionation.
authors.affiliation: University of Marburg, Department of Chemistry, Hans-Meerwein-Straße, D-35032 Marburg, Germany. Electronic address: pyellu@staff.uni-marburg.de.
authors.forename: Ute
authors.initials: U
authors.lastname: Pyell
authors.affiliation: University of Marburg, Department of Chemistry, Hans-Meerwein-Straße, D-35032 Marburg, Germany.
authors.forename: Alaa H
authors.initials: AH
authors.lastname: Jalil
authors.affiliation: University of Marburg, Department of Chemistry, Hans-Meerwein-Straße, D-35032 Marburg, Germany.
authors.forename: Dominic A
authors.initials: DA
authors.lastname: Urban
authors.affiliation: University of Marburg, Department of Physics, Renthof 7, D-35032 Marburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Pfeiffer
authors.affiliation: University of Marburg, Department of Physics, Renthof 7, D-35032 Marburg, Germany.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Pelaz
authors.affiliation: University of Marburg, Department of Physics, Renthof 7, D-35032 Marburg, Germany.
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Parak
keywords: Asymmetric flow field-flow fractionation; Capillary electrophoresis; Colloidal nanoparticles; Hydrodynamic radius distribution; Ionic drag coefficient; Relaxation effect; Taylor dispersion analysis; Zeta potential