The effects of polymer properties on DNA separations by capillary electrophoresis in uncross-linked polymer solutions

Low-viscosity, aqueous solutions of hydrophilic linear polymers have been shown to be useful for the separation of DNA restriction fragments by capillary electrophoresis (CE). However, the choice of polymer type, size, and concentration remains largely empirical, because the mechanism of high-field electrophoretic DNA separations in polymer solutions is not well understood. To assist in elucidating the mechanism of DNA separation, we experimentally investigated the effects of polymer properties such as stiffness (persistence length), average molecular mass, polydispersity, and hydrophilicity on the separation of DNA ranging from 72 bp to 23 kbp. This was accomplished by comparing the results of DNA separations obtained by counter-migration CE in dilute and semidilute solutions of linear polyacrylamide (PAA), hydroxyethyl-cellulose (HEC), and hydroxypropylcellulose (HPC) polymers of several different average molecular masses.