MICELLAR ELECTROKINETIC CHROMATOGRAPHY-MASS SPECTOMETRY FOR HIGH SENSITIVE QUANTITATIVE AND QUALITATIVE DETECTION OF NEUTRAL ANALYTES

胶束电动色谱（MEKC）是毛细管电泳（CE）的一种模式，能够通过电泳分离中性分析物。MEKC是通过在毛细管区带电泳（CZE）运行液中加入离子表面活性剂来实现的，其分离原理是基于分析物在离子胶束和周围水相之间的分配。运行溶液中存在表面活性剂会给质谱检测带来问题，因为表面活性剂的浓度过高会降低CE和质谱（MS）之间的电喷雾电离（ESI）界面的电离效率，而ESI是CE-MS唯一可商用的界面。基于毛细管中间断运行的溶液之间分析物迁移率的差异，已经开发了几种在线样品浓缩技术来提高CZE的浓度灵敏度，但是这些技术不适用于中性分析物，因为它们没有电泳迁移率。本研究的目的是开发MEKC的质谱检测技术，作为一种高灵敏度的定量和定性检测方法。研究的另一个目的是开发在线样品浓度技术，如果MEKC，以提高大多数检测方法的检测灵敏度。MEKC-MS是一种配备特殊设计的常压化学电离（APCI）界面的质谱仪，其效率不受表面活性剂存在的显著高浓度的影响，使用另一种配备ESI界面的质谱仪。如果使用多种技术优化条件，MEKC-MS可以用于多种不同的分析物，但技术包括仪器必须进一步发展，以方便操作。MEKC的在线样品浓度非常成功：一种名为“扫描”的新浓度技术可以根据分析物与胶束的亲和力将峰高的检测灵敏度提高3到5个数量级。将在线样品浓缩技术与MEKC-MS相结合，以提高MS检测的可检出性。少

Micellar electrokinetic chromatography (MEKC) is a mode of capillary electrophoresis (CE) and is capable of separating neutral analytes by electrophoresis. MEKC is performed simply by adding ionic surfactant to the running solution of capillary zone electrophoresis (CZE) and its separation principle is based on the partitioning of the analytes between the ionic micelle and the surrounding aqueous phase. The presence of the surfactant in the running solution causes problems in mass spectrometric detection, because the significant high concentration of the surfactant deteriorates the ionization efficiency of the electrospray ionization (ESI) interface between CE and mass spectrometry(MS), which is the only one commercially available interface for CE-MS. Several on-line sample concentration techniques have been developed to improve concentration sensitivity in CZE on the basis of the difference in mobilities of the analytes between the discontinuous running solutions in the capillary, but … More these techniques are not applicable to neutral analytes because they do not have electrophoretic mobility. The purpose of this research is to develop techniques for mass spectrometric detection in MEKC as a high sensitive quantitative and qualitative detection method. Another aim of the research is to develop on-line sample concentration techniques if MEKC to improve detection sensitivity in most detection methods. To develop MEKC-MS, a MS instrument equipped with a specially designed atmospheric pressure chemical ionization (APCI) interface, which efficiency is not affected by the presence of significantly high concentration of the surfactant, another new MS instrument equipped with ESI interface were utilized. MEKC-MS was possible for several different analytes if the conditions are optimized by using several techniques, but the technique including instruments must be further developed for easy operation. On-line sample concentration in MEKC was very successful : a new concentration techniques named "sweeping" can enhance the detection sensitivity more than 3 to 5 orders of magnitude in terms of peak heights depending on the affinity of the analytes with the micelle. The combination of the on-line sample concentration techniques and MEKC-MS will be developed to improve the detectability of MS detection. Less