Kaneta Takashi, Ueda Takeshi, Hata Kazuki, Imasaka Totaro
Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan.
J Chromatogr A. 2006 Feb 17;1106(1-2):52-5. doi: 10.1016/j.chroma.2005.08.062. Epub 2005 Sep 8.
A hydrophilic polymer, poly(vinylpyrrolidone) (PVP), was employed for suppressing the electroosmotic flow (EOF). A capillary was filled with aqueous PVP solution for coating the capillary wall with PVP; the PVP solution was then replaced by a migration buffer solution containing no PVP. Three types of PVP with different molecular weights were examined. The EOF was suppressed more effectively as the molecular weight of PVP increased. The EOF in the coated capillary was approximately 10-fold smaller than that of a bare capillary and was constant in the pH range of 6-8. The suppressed EOF was stable even when no PVP was added to the migration buffer. However, the EOF increased significantly when sodium dodecyl sulfate was added into the migration buffer. The method was applied for determining the electrophoretic mobilities of inorganic anions that have negative electrophoretic mobilities larger than the electroosmotic mobility of the bare capillary. A novel method for determining the electrophoretic mobilities was proposed based on the linear relationship between electric current and electrophoretic mobility. The electrophoretic mobility was proportional to the electric current. Therefore, the intercept of the regression equation represents the electrophoretic mobility at room temperature. The electrophoretic mobilities were in good agreement with the absolute electrophoretic mobilities.
使用一种亲水性聚合物聚乙烯吡咯烷酮（PVP）来抑制电渗流（EOF）。将毛细管填充PVP水溶液以用PVP涂覆毛细管壁；然后用不含PVP的迁移缓冲溶液替换PVP溶液。研究了三种不同分子量的PVP。随着PVP分子量的增加，EOF得到更有效的抑制。涂覆毛细管中的EOF比未涂覆毛细管中的EOF小约10倍，并且在pH值6 - 8范围内保持恒定。即使在迁移缓冲液中不添加PVP，被抑制的EOF也是稳定的。然而，当在迁移缓冲液中加入十二烷基硫酸钠时，EOF显著增加。该方法用于测定无机阴离子的电泳迁移率，这些无机阴离子的负电泳迁移率大于未涂覆毛细管的电渗迁移率。基于电流与电泳迁移率之间的线性关系，提出了一种测定电泳迁移率的新方法。电泳迁移率与电流成正比。因此，回归方程的截距代表室温下的电泳迁移率。电泳迁移率与绝对电泳迁移率吻合良好。
