Size-dependent retardation and resolution by electrophoresis of rigid, submicron-sized particles, using buffered solutions in presence of polymers: a review of recent work from the authors' laboratory.

Abstract

Capillary zone electrophoresis (CZE) was conducted in buffered solutions of polyacrylamide (PA) and polyethylene glycol (PEG) to find the degree and the manner in which separation and resolution of submicron-sized rigid spherical polystyrene sulfate and carboxylate particles were affected by the presence of those polymers. In resolving pairs of representative particles, maximal resolution was observed at or near the entanglement threshold concentration, c*, of the polymer. The value of that maximum represents a several-fold increase in resolution. Since c* can be calculated from intrinsic viscosity, and the latter from the molecular weight of the polymer (and some constants available in the literature), optimally resolving polymer conditions become predictable. The maximum can also be experimentally determined by measuring intrinsic viscosity and calculating c*, or by either systematically varying the concentration of a polymer of constant molecular weight or by varying the molecular weight of a polymer at constant concentration. An optimally resolving field strength is superimposed on the maximally resolving condition of polymer concentration and weight.