Mixed triblock copolymers used as DNA separation medium in capillary electrophoresis

Abstract

A polymer solution, formed by mixing two polyoxybutylene–polyoxyethylene–polyoxybutylene (BEB) triblock copolymers (B 10E 270B 10 and B 6E 46B 6), was tested as a new separation medium for double-stranded DNA separation in capillary electrophoresis. The mixture of B 10E 270B 10 and B 6E 46B 6 has a viscosity-adjustable property and a dynamic coating ability, which makes the medium very easy to handle. The performance of the mixture on the DNA separation is greatly affected by the mass ratio of the two constituents. There is a minimum amount of concentration for B 10E 270B 10, below which the medium will lose its performance. The addition of B 6E 46B 6 increases both the selectivity and the separation efficiency. The optimal concentration, with 3% (w/v) B 10E 270B 10 and 5% (w/v) B 6E 46B 6, is determined with the consideration of both speed and resolution. A resolution of 1.3 was achieved on the separation of 123/124 base pairs in the pBR322/HaeIII digest within 20 min by using a 10 cm column of 75 μm I.D., demonstrating the potential use of mixtures of amphiphilic block copolymers as an effective DNA separation medium.