Characterization of Electrophoretic Sample Transfer from a Capillary to an Ultrathin Slab Gel

The capillary-to-gel transfer region of the capillary-ultrathin slab gel system appears to control the lateral dispersion of the DNA plugs and therefore the maximum number of simultaneous separations. The capillary-to-gel transfer region has been examined in detail in an attempt to minimize the lateral dispersion. Since the capillary and ultrathin slab gel potential fields are independently controlled, the effect on plug width perpendicular to the direction of migration and the time for each plug of DNA to migrate from the capillary to the gel at various capillary potentials is considered. In 57-μm gels, when the capillary potential field is equal to or higher than the gel potential field, the plugs widen and the time for a DNA sample to transfer into the gel increases. A similar trend is observed with 25-μm gels, although due to the mismatch between the capillary bore and the gel thickness, the lateral dispersion is even greater than in the 57-μm gels.