Application of Capillary Electrophoretic On-Line Sequential Concentration Based on Micelle to Solvent Stacking

Shan Sun,Zhe Yuan,Yuanqi Lu,Qingqiang Yao

doi:10.4236/ajac.2018.91005

Abstract

To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was reviewed. MSS has been coupled to sweeping FASS, FASI and normal EKI. Furthermore, multiple stacking by coupling MSS with more than one stacking method has also been reported. It is more sensitive and selective than solely used of one or two stacking methods and is very suitable for complex and trace sample analysis.

Highlights

Due to its small volume and the narrow optical path, Capillary Electrophoresis (CE) suffers from poor concentration sensitivity, especially when on-line UV detection is utilized [1] [2]
Sweeping-micelle to solvent stacking (MSS) was first introduced by Quirino to determine four β-blockers and two tricyclic antidepressant drugs with capillary zone electrophoresis (CZE)separation [13] and they have been widely used in organic cations [13] [14] [15] and anions [29] [30] analysis
If there is no apparent difference in conductivity between the sample zone and the background electrolyte (BGE), the samples can be introduced with the aid of micelles, during which the effects of electroosmotic flow (EOF) can be attenuated by introducing acidic buffer solution [23] [24] or with the assistance of pressure during EKI [25]

Summary

Introduction

Due to its small volume and the narrow optical path, CE suffers from poor concentration sensitivity, especially when on-line UV detection is utilized [1] [2]. To enhance the detection ability of CE, a number of on-line concentration techniques have been developed These techniques are based on the changes in the analyte migration velocity at the boundary between sample zone and the background electrolyte [3] [4]. Because the organic solvent in the background electrolyte (BGE) affects the micellar interaction with the analytes, the effective electrophoretic directions of the analytes will reverse at the micellar to solvent stacking boundary (MSSB), causing the analytes focusing [5] [6]. Compared to single used of MSS, the sequential stacking techniques can enhance the sensitivity 2 - 10 more times and these methods can be more selective to specific analytes The developments of these sequential techniques have been included in the review of Yang et al [28]. The application of sequential on-line concentration methods based MSS was reviewed

Sweeping-MSS

Micelle to Solvent Stacking via Normal Electrokinetic Injection

MSS Based Multiple Stacking

Conclusion