Influence of Mannitol Additive on DNA Separation by Capillary Non Gel Sieving Electrophoresis
甘露醇添加剂对毛细管无胶筛分电泳分离DNA的影响

Polymer solutions with high concentration were employed as sieving buffer in order to obtain satisfactory separation of smaller DNA fragments with length of less than 1,000 base pairs. The concentrated polymer solution had very high viscosity, which was difficult to be pumped into or out of the capillary. Mannitol additive can enhance the sieving ability of hydroxy-propylmethylcellulose (HPMC) solution in a Tris-Borate-EDTA background electrolyte. With the existence of mannitol, good separation of PGEM-3Zf(+)/Hae III was able to be obtained in a less concentrated HPMC solution with relatively low viscosity. The optimum mass concentration of mannitol was investigated and it was found that 60 g/L mannitol could give the best results. Mannitol chain could be formed through hydrogen bond among mannitol, HPMC and borate. This kind of mannitol chain shaped the network and decreased the pore size, so the separation was greatly enhanced.