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Unusual stacking with electrokinetic injection of cationic analytes from micellar solutions in capillary zone electrophoresis

Citation

Wuethrich, A and Quirino, JP, Unusual stacking with electrokinetic injection of cationic analytes from micellar solutions in capillary zone electrophoresis, Analytical and Bioanalytical Chemistry, 408, (30) pp. 8663-8668. ISSN 1618-2642 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 Springer-Verlag Berlin Heidelberg

DOI: doi:10.1007/s00216-016-9735-1

Abstract

Electrokinetic injection (EKI) in capillary zone electrophoresis (CZE) of charged analytes is by the electroosmotic flow (EOF) and electrophoretic mobility of analytes. In most forms of stacking with EKI, the sample ions were introduced via electrophoretic mobility and concentrated in a stacking boundary inside the capillary. In this work, we describe the unusual stacking of cationic analytes via EKI of sodium dodecyl sulfate (SDS) micelles into a fused silica capillary filled with acidic background solution (BGS) with 40-50 % acetonitrile. The analytes prepared with SDS micelles were injected because of their interaction with micelles or effective electrophoretic mobility. We observed two peaks from an analyte, and this suggested the concentration of analytes into two stacking zones. These two adjacent stacking zones were surprisingly maintained inside the capillary during EKI although the EOF was moving towards the inlet. The zones were identified as the SDS micelles (micelles zone) and organic solvent-rich stacking zone (solvent-rich zone) where the micelles zone was closer to the inlet end of capillary. The analytes concentrated in the solvent-rich zone through the mechanism of micelle to solvent stacking (MSS). The concentrated analytes in the micelles zone were from the concentrated analytes that electrophoretically migrated into the micelles zone from the solvent-rich zone during EKI. The analytes in the micelles zone were then re-stacked by MSS and formed the second sharp peak in CZE. This was prevented by reduction of acetonitrile concentration in the inlet BGS. A sensitivity enhancement factor of more than 100 was obtained for model cationic drugs (diphenhydramine and imipramine).

Item Details

Item Type:Refereed Article
Keywords:analysis
Research Division:Chemical Sciences
Research Group:Analytical Chemistry
Research Field:Separation Science
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
Author:Wuethrich, A (Mr Alain Wuethrich)
Author:Quirino, JP (Associate Professor Lito Quirino)
ID Code:114834
Year Published:2016
Funding Support:Australian Research Council (FT100100213)
Deposited By:Chemistry
Deposited On:2017-02-28
Last Modified:2017-11-01
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