Electrophoretic separation of linear and supercoiled DNA in uncoated capillaries

We report electrophoretic separation of supercoiled plasmids (2-16 kilo bas e pairs) and linear double-stranded DNA (0.6-23 kilo base pairs) in uncoate d capillaries filled with dilute hydroxyethylcellulose. Because electroosmo tic flow reverses the order of elution, long plasmids spend less time in th e capillary and their bandwidths are narrower than observed in coated capil laries. However, resolution is similar to that obtained in coated capillari es, because it is governed by the distribution of unresolved topoisomers. I n the presence of electroosmotic how migration of supercoiled plasmids does not follow the elastic rod model that has been observed in coated capillar ies. (C) 1999 Elsevier Science B.V. All rights reserved.