EXPERIMENTAL-STUDY ON THE RETENTION OF SILICA PARTICLES IN GRAVITATIONAL FIELD-FLOW FRACTIONATION - EFFECTS OF THE MOBILE-PHASE COMPOSITION

Effects of mobile phase composition can play an effective role in modu lating the retention of particles in gravitational field-flow fraction ation (GFFF), the simplest and cheapest among field-flow fractionation (FFF) techniques. In the framework of an optimized procedure for the GFFF characterization of particulate systems, an experimental approach to the effects of the mobile phase composition on the retention of si lica particles retention is presented. The role of the ionic strength and the presence of surfactant are emphasized, with special regards to the shape of the particles. Moreover, the first experimental evidence of potential-barrier GFFF is reported.