Imidazolium ionic liquids as dynamic and covalent modifiers of electrophoretic systems for determination of catecholamines

Ekaterina Kolobova; Liudmila Kartsova; Anastasia Kravchenko; Elena Bessonova

doi:10.1016/j.talanta.2018.05.057

Imidazolium ionic liquids as dynamic and covalent modifiers of electrophoretic systems for determination of catecholamines

Talanta. 2018 Oct 1:188:183-191. doi: 10.1016/j.talanta.2018.05.057. Epub 2018 May 18.

Authors

Ekaterina Kolobova¹, Liudmila Kartsova², Anastasia Kravchenko², Elena Bessonova²

Affiliations

¹ Saint Petersburg State University, Institute of Chemistry, 26 Universitetskii prospect, St. Petersburg, Petergof 198504, Russia; The Federal State Institute of Public Health 'The Nikiforov Russian Center of Emergency and Radiation Medicine', The Ministry of Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters, 54, Optikov st., St. Petersburg 197082, Russia. Electronic address: ekatderyabina@mail.ru.
² Saint Petersburg State University, Institute of Chemistry, 26 Universitetskii prospect, St. Petersburg, Petergof 198504, Russia.

PMID: 30029362
DOI: 10.1016/j.talanta.2018.05.057

Abstract

The subject of this study is comparison of imidazolium based dynamic and covalent coatings of the quartz capillary wall on the example of catecholamines determination. A way of synthesis of covalent coatings was proposed. For the first time different type of on-line sample preconcentration techniques (field-amplified sample stacking (FASS), head-column field amplified sample stacking (HC FASS), electrostacking, sweeping) were performed for catecholamines determination in N-alkylsubstituted imidazolium coated capillary. It was found that long chain imidazolium ionic liquids (C₁₂MImCl and C₁₆MImCl) in background electrolyte content create a dynamic coating of the quartz capillary walls and generate anode electroosmotic flow. Same is true for covalent coatings based on N-alkylsubstituted imidazolium. Both coatings prevent sorption of catecholamines on the internal surface of the quartz capillary. As a result efficiency and peak symmetry are increased. The maximum stacking efficiency factor (SEF) values for dynamic coatings were in range of 70-85, and limits of detection (LODs) were about 0.05 µg/ml under sweeping condition (micelle forming agent - C₁₆MImCl) when the electric conductivity of sample matrix was higher than electric conductivity of BGE. In case of covalent coating, the maximum SEF values were higher than 1000, and LODs were about 1-2 ng/ml under sweeping condition (micelle forming agent - sodium dodecyl sulphate) in combination with electrostacking.

Keywords: Capillary electrophoresis; Catecholamines determination; Dynamic and covalent coatings of the quartz capillary wall; Imidazolium ionic liquids.