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

Capillary zone electrophoresis (CZE) was conducted in buffered solutions of polyacrylamide (PA) and polyethylene glycol (PEG) to find the degree and t he manner in which separation and resolution of submicron-sized rigid spher ical polystyrene sulfate and carboxylate particles were affected by the pre sence of those polymers. In resolving pairs of representative particles, ma ximal resolution was observed at or near the entanglement threshold concent ration, c*, of the polymer. The value of that maximum represents a several- fold increase in resolution. Since c* can be calculated from intrinsic visc osity, and the latter from the molecular weight of the polymer (and some co nstants available in the literature), optimally resolving polymer condition s become predictable. The maximum can also be experimentally determined by measuring intrinsic viscosity and calculating c*, or by either systematical ly varying the concentration of a polymer of constant molecular weight or b y varying the molecular weight of a polymer at constant concentration. An o ptimally resolving field strength is superimposed on the maximally resolvin g condition of polymer concentration and weight.