中文摘要：

本实验以羟乙基纤维素（HEC）为筛分介质,以100～1500 bp DNA ladder为分离对象,系统地研究了直流电场下毛细管电泳时DNA分离特性.论文考察了DNA迁移淌度及分离度随HEC溶液浓度和分子量、毛细管两端电场强度（E）、毛细管有效长度（le）及其内径形状、背景电解液（BGE）温度等因素变化规律.研究发现：（1）当筛分介质HEC浓度高于其阈值浓度c＊时,HEC分子量越大,相邻DNA片段之间淌度差越大,HEC浓度越高,其迁移淌度越低;（2）对于相邻的DNA片段,le在一定范围内,其分离度随le增大而线性升高;（3）毛细管有效长度一定时,DNA淌度随毛细管侧面积与截面积之比R增大而升高,分离效率提高;（4）BGE温度升高,DNA在筛分介质中扩散效应增强,迁移淌度变大,相邻DNA片段间分离度减小.根据以上结论,在直流电场下毛细管电泳φ×174-Hirc II限制性酶切片段,并实现了其高分离度、快速分离.

英文摘要：

Using hydroxyethylcellulose（HEC） solution as polymer matrix,this work systematically studied the separation performance of 100 base pairs（bp） DNA ladder（100～1500 bp） by direct current electric field capillary electrophoresis（CE）.In the present paper,we systematically investigated the influence of polymer concentration and molecular weight of HEC,electric field strength（E）,the effective length（le） and the shape of the capillary,the temperature of the background electrolyte（BGE） on the separation performance of DNA.Furthermore,we compared the migration of DNA in polymer with the non-gel sieving model.Results show that：（1） When the concentration of HEC is above the entangled threshold c＊,the mobility difference increases with the growth of molecular weight,whereas the mobility of DNA decreases with the rise of concentration of HEC.（2） The resolution of adjacent DNA fragments linearly increases with the effective length（le） of the capillary when le ranges from 4 to 12 cm.（3） The mobility of DNA increases with the growth of area ratio R（Slateral/Ssection）,and thus the separation performance improves.（4） The increase of BGE temperature strengthens the diffusion effect of DNA,thus increases the mobility,and deteriorates the resolution.Based on the results above,we separated the φ×174-Hirc II digest by CE in an optimal electrophoretic condition.Experiment shows that rapid separation of φ×174-Hirc II digest was realized with high resolution.In our experiment,the fused-silica capillary is coated by acrylamide,and the background electrolyte（BGE） used for the sieving matrix contains 0.5×Tris-borate-EDTA（TBE） and 1×SYBR Green I.The DNA sample was injected for 2.0 s at an E of 100 V/cm.The self-build CE device involved is reliable and showed some remarkable achievements previously.Such a study is beneficial to the realization of rapid and effective separation of DNA,and allows deep insight into DNA migration in the polymer matrix under constant electric fi