The water-soluble mixtures of polymers, poly(N,N-dimethylacrylamide) (PDMA)/polyvinylpyrrolidone (PVP), were synthesized and used in capillary electrophoresis (CE) for DNA separation. With the optimal concentration of PDMA/PVP polymer solution, the doublet of 123/124 bp in pBR322/Hae Ⅲ Markers could be separated with UV detector and the resolution value was 0.72. When the denaturant formamide (φ≥0.10) was added in the polymer solution, DNA fragments of 123/124 could be also separated well with the resolution as 0.75, which quite met the requirement of DNA sequencing (R_s>0.59). In addition, the lower viscosity of the polymer solution made the practice easier. The sample stacking effect was validated in the experiments. The medium showed single-base-pair DNA separation by capillary electrophoresis even with ultraviolet detector and uncoated capillary column.

Key words: capillary electrophoresis, non-gel sieving, synthetic polymer, DNA separation, UV detector, single-base-pair separation