ELECTROMIGRATION BEHAVIOR OF DNA-MOLECULES AT THE FREE ELECTROLYTE-POLYMER SOLUTION INTERFACE

The velocity at which DNA molecules migrate across an interface betwee n a free solution of an electrolyte and a sieving medium was investiga ted in capillaries. A model was proposed where the DNA molecules are s upposed to be stacked at the interface and then, due to consecutive co nformational changes, their velocities increase and reach the value of their effective electrophoretic mobilities in the polymer solution fi lling the rest of a capillary. This behaviour was shown by measuring t he electromigration injection bias and by extrapolation of the migrati on times in capillaries of different lengths to the zero migration pat h. The experiments showed an extraordinarily high size-based separatio n selectivity of the electromigration across the interface, which seem s to offer a potential for successful high resolution separation of DN A fragments in capillaries as short as several centimetres.