Experimental and theoretical studies of DNA separations by capillary electrophoresis in entangled polymer solutions

Studies of electrophoretic separations of DNA restriction fragments by capillary electrophoresis in solutions of (hydroxyethyl) cellulose (HEC) were performed. Rheological studies were used to confirm that the entanglement threshold (phi*) for the HEC solutions used is approximately 0.004 g/mL, in good agreement with theoretical predictions. A mesh size an order of magnitude smaller than that found in agarose gels (on a per weight basis) was calculated using polymer-entanglement theory and was confirmed by electrophoretic measurements. Electrophoretic migration was shown to follow the Ogston regime under most conditions. An approach for obtaining smaller mesh sizes is presented.