Electrophoretic focusing on inverse electromigration dispersion gradient. The fundamental resolution equation and pressure - assisted performance enhancement

0491052 - ÚIACH 2019 SK eng A - Abstrakt
Malá, Zdeňka - Gebauer, Petr
Electrophoretic focusing on inverse electromigration dispersion gradient. The fundamental resolution equation and pressure - assisted performance enhancement.
Book of abstracts. 24th International Symposium on Separation Sciences (ISSS 2018). Bratislava: Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, 2018 - (Hutta, M.; Bodor, R.; Halko, R.). s. 140-140. ISBN 978-80-971179-8-6.
[International Symposium on Separation Sciences /24./ - ISSS 2018, International Conference Analytical Methods and Human Health /21./ - AMHH 2018. 17.06.2018-20.06.2018, Jasná]
Grant CEP: GA ČR(CZ) GA16-09135S
Institucionální podpora: RVO:68081715
Klíčová slova: capillary electrophoresis * electrophoretic focusing * electromigration dispersion * ESI-MS detection
Obor OECD: Analytical chemistry

Electrophoretic focusing on inverse electromigration dispersion (EMD) gradient is a new analytical technique based on a unique separation principle where weak non-amphoteric ionogenic species are focused, separated and transported to the detector by an EMD profile of suitable properties. The present work extends the theoretical description of this method by introducing the concept of resolution and deriving the fundamental equation expressing resolution as function of basic system parameters. The results indicate that most important for practice at constant current operation is that resolution is
proportional to the square root of time. For variable current regimes (e.g. constant voltage), the time variable is replaced by the product of electric current and passed electric charge at detection time. Computer simulations for a model pair of substances support the validity of the presented theory and confirm the theoretical conclusion that resolution can be increased by allowing longer electromigration of the gradient in terms of time or passed charge. The experimental example shown comprises an anionic electrolyte system based on maleic acid and 2,6-lutidine, combined with ESI-MS detection and operated in the reverse mode due to strong electroosmotic flow and ESI suction. The practical implementation of the proposed methodology is done by application of negative pressure at the inlet vial, resulting in very
substantial resolution enhancement and baseline separation of otherwise unresolved substances. The performance and high sensitivity of the developed technique is demonstrated on the example of simultaneous analysis of four sulfonamides and three dichlorophenols in waters with limits of detection on the 1 nM level.
Trvalý link: http://hdl.handle.net/11104/0285133