Method of preparative, Kohlrausch-regulated electrophoresis using polyethylene glycol derivatized trailing ions

In a Kohlrausch-regulated electrophoresis method wherein a mixture containing at least two macromolecular components to be separated is placed in a layer between a pair of physically distinct separate layers respectively including a leading ion and a trailing ion, the mobility of said leading ion being greater than that of said components, the mobility of said trailing ion being less than that of said components, and a direct current passed through said layers to effect separation of said components with said components being adjacent one another, the improvement which comprises employing as said trailing ion a non-aromatic, acyclic, substantially linear, at least partially water dispersible polymer which is compatible with said components, contains recurring ethylene oxide groups and at least one terminal group which is charge-bearing during said current passage, the mobility of said polymer being substantially independent of pH over a range of at least about 4 pH units, and with the mobility of the entirety of said trailing ion being less than the mobility of all of said components being separated.