Capillary Electrophoresis of DNA Fragments with Replaceable Low-Gelling Agarose Gels

Capillary electrophoresis (CE) in all its various modes is routinely used in the area of life science for the analysis of wide spectra of species ranging from small inorganic/ organic molecules to multi-subunit proteins and mega-size DNA (1 ). Capillary gel electrophoresis (CGE) is the counterpart of gel electrophoresis in the slab-gel format. Similar molecules are analyzed with CGE as with slab gels, like SDS-protein complexes and single-stranded/duplex DNA. Since these analytes have similar mass-overcharge ratio and therefore similar mobilities (for ≥10 bases in length, depending on pH and base composition) they can not be separated in a carrier-free system like capillary free-zone electrophoresis (2 ), although some exceptions are known (3 ,4 ). A size-sieving medium is therefore necessary to impart hydrodynamic friction on the migrating molecules for their separation. The constraint of the capillary format also acts to prevent convection, whereas in the slab-gel format the sieving matrix plays this role.