摘要
在同系物方法测定胶束迁移速度（ｌ／ｔｍ ｃ ） 的基础上提出了一种同时求算电渗流速率（ｌ／ｔ０） 的ｔ０ 和ｔｍ ｃ 的新方法， 该法在选择同系物标记物较为适当时， 可以得到更为准确的结果。同时可以减少由ｔ０ 测定而带来的误差。 实验结果表明， 采用甲醇等标记物测定电渗流速率时， 由于其在胶束中的溶解使得实测结果较真值偏大，而由此计算得到的ｔｍ ｃ 值偏低。ｔ０ 、ｔｍ ｃ 皆与缓冲液的种类和浓度有关， 这可能是由于缓冲液组成的变化不仅使得离子强度改变， 也使柱管壁和胶束表面的ξ势发生变化所致。同系物标记物的选择对ｔ０ 、ｔｍｃ 测定精度影响的讨论也为实际分析系统ｔ０ 、ｔｍｃ 的测定和分析分离条件的优化选择提供了必要的理论依据。
A new method for the simultaneous calculation of electroosmotic flow rate (l/t0) and micellar mobility (l/tmc) in MECC has been developed on the basis of Michelle's homologues method for the determination of tmc. If homologous markers are properly selected, more accurate values of t0 and tmc can be obtained. The method simplifies the traditional procedure for tmc determination, and reduces the errors in t0 determinations. Experiments show when used methanol as marker compound, the calculated tmc value is biased to a smaller value. This could be explained by the dissolution of the marker compound in the micelle phase that makes the experimental t0 larger than truth value. Both t0 and tmc depend on the buffer species and concentration, since a change in buffer species and concentration could affect not only its ionic strength, but also the potential of the micelle surface and the capillary wall. The discussion on the relationship between homologous series and the tmc values is helpful for separation condition optimization and for obtaining accurate t0 and tmc values. It is recommended to have a wide marker concentration range and a large number of homologues used.
出处
《分析测试学报》
CAS
CSCD
1999年第6期13-16,共4页
Journal of Instrumental Analysis
关键词
电渗流
胶束
迁移速度
同系物
标记物
MECC
Micellar electrokinetic capillary chromatography(MECC), Electroosmotic flow, Micellar mobility, Homologous series, Marker
