New concept in focusing field-flow fractionation and thin layer isopycnic focusing: Coupling of primary electric field with secondary gravitational force

A new concept of isopycnic focusing exploiting the simultaneous action of coupled electric and gravitational fields is described. Experimental implementation of this concept is demonstrated under conditions of focusing field-flow fractionation and of newly proposed thin layer isopycnic focusing. Both methods are aimed for particle separations. Although the demonstration was performed by using model cross-linked polymer and latex particles, the most important field of potential applications is intended for analytical and preparative separations of biological particles.     

Experimental study of isopycnic focusing generated by coupled electric and gravitational field forces: Use in thin layer focusing and focusing field-flow fractionation

Various operational parameters affecting the formation of the density gradient generated by the electric field action on a binary pseudo-continuous carrier liquid composed of charged colloidal silica particles suspended in water and the isopycnic focusing of sample particles were investigated under conditions of static thin layer focusing and dynamic focusing field-flow fractionation. The properties and the behavior of the density gradient forming carrier liquid were studied. The experimental results are compared with theoretical predictions and discussed with respect to potential applications of the proposed concept not only for separation purposes but also for studies of interparticle interactions.