Preparative-scale purification of DNA restriction fragments by continuous-flow gel electrophoresis

A method is described for large-scale (10-100 micrograms) purification of individual DNA fragment lengths from a mixture of fragment lengths using a continuous-flow, toroidal gel electrophoresis system that is commercially available. Preparative-scale separations of fragments up to approximately 1000 bp differing in length by as little as 100 bp are obtained. Typical recoveries of purified DNA fragments range from 25% to 40% of starting material.