毛细管区带电泳中场增强进样柱内富集的非线性特征

摘要

直接柱头场效应进样是一种毛细管区带电泳柱内富集,其进样过程中样品在柱内的分布可分为两部分,即在运行缓冲溶液中的堆积区段和由电渗流引入的样品溶液区段.通过对溶质输运行为的研究表明:两区段长度与进样时间之间并非简单的线性关系,因此进样量与进样时间的关系也非线性,且与溶质淌度有关;进样量的增加并不能导致富集倍数的同步增加,由于层流的作用使得场效应进样柱内富集效果降低.为了在保持柱效基本不变情况下得到好的富集效果,除需使溶质在运行缓冲溶液和样品溶液中的电导率比极大外,进样时间也应与之匹配.%FASS(field amplified sample stacking) is a technique for on-column enrichment in capillary zone electrophoresis. The distribution of solute in column during injection can be divided into two parts: the stack zone in running buffer and the sample solution zone imported by electroosmosis. Based on the investigation of transfer of solute in column, the results showed that the relationship between the length of two zone and injection time was nonlinear, so the relationship of injecting size that related with the mobility of solute and injection time. The increasing of the enrichment effect will not synchronize with the increasing of injection size, and the enrichment effect is decreased due to the laminar flow. To hold a basic constant column efficiency and desire enrichment effect, the ratio of mobility of solute in two zones should be maximum, and the injection time should also match with the ratio.