Authors: S. Losert, K. Hungerbühler, N. Bendixen, A. Ulrich
Affilation: EMPA, Switzerland
Pages: 155 - 158
Keywords: asymmetric flow field flow fractionation, membrane particle interaction, zeta-potential
Asymmetric flow field flow fractionation is a powerful and promising technique for the separation of nanoparticles. In combination with UV/Vis detection, multi-angle light scattering and coupled to ICP-MS it is a fast and quantitative analytical method for analyzing particle size, size-distribution and elemental composition. Nevertheless there are two big disadvantages. First the unpredictable particle loss due to deposition of particles on the membrane. Second, different membrane particle interactions lead to shifts in retention time, which has than an influence on the size calibration, when certified standard reference materials are used for size calibration. These problems can be found in a lot of publications dealing with A4F as a detection method for nanoparticle analysis. A possible explanation for these unspecific interactions could be the ζ-potential as well of the particles as of the membrane material itself. Such potential measurements can characterize the electro-kinetic properties of a membrane surface. So the ζ-potentials of typical used membranes with different cutoffs were analyzed within this work. Furthermore SEM pictures of the samples were recorded to get an idea about the surface of the membrane and to establish the results achieved from the ζ-potential measurements.