Application of 1-alkyl-3-methylimidazolium-based ionic liquids in separation of bioactive flavonoids by capillary zone electrophoresis

Abstract

Room-temperature ionic liquids (ILs) are liquids that are constituted entirely of ions and can provide a solvent environment quite unlike any other available at room temperature. They continue to attract considerable interest in the chemistry research community as they are good solvents for a wide range of both inorganic and organic materials. In this study, a CZE method has been established for resolving natural flavonoids, quercetin, kaempferol and isorhamnetin in the Chinese herbal extract from Hippophae rhamnoides and its medicinal preparation (Sindacon Tablet). In this method, 1-alkyl-3-methyl-imidazolium-based ILs are used as the additive, and the effects of the alkyl group, imidazolium counterion (anionic part), along with the concentration of IL are investigated and discussed. Baseline separation, high efficiencies and symmetrical peaks of the three flavonoids were obtained. The separation mechanism seems to be the hydrogen-bonding interaction between the imidazolium cations of IL and the flavonoids.

Extraction, separation, and detection methods for phenolic acids and flavonoids

“…A CZE method was established for resolving natural flavonoids in a Chinese herbal extract using 1-alkyl-3-methyl-imidazolium-based ionic liquids as additives [197]. Baseline separation, high efficiencies, and symmetrical peaks were obtained for the flavonoids.…”

“…Electropherograms of (A) a mixture of flavonoids, (B) an extract of Hippophae rhamnoides and (C) an extract of medicinal preparation, Sindacon tablet, using 1-alkyl-3-methyl-imidazolium-based ionic liquids, as the additive in 20 mM borate buffer, pH 10. 1: IS, isorhamnetin; 2: KA, kaempferol; 3: QU, quercetin [197].…”

Property of ionic liquid in electrophoresis and its application in chiral separation on microchips

“…The other application of RTILs was related to the stationary phase [14] or the solvent for stationary phase [15] in GC. In CE, mostly researches were centralized in using RTILs as the analytes [16][17][18][19][20][21][22] or additives [23][24][25][26][27][28][29]. People had confirmed the addition of RTILs in electrolytes ameliorated the electrophoretic separation.…”

“…It had been found that the migration times of the analytes attributed to the positive charged groups coating on the inner surface of capillary and the free ions in bulk solution [21] in CE. As the additives in EKC, some surfactants of RTILs were applied to achiral and chiral separation of binaphthyl derivatives [23] and determine bioactive flavonoids [29]. Several novel chiral ionic liquids were synthesized for micellar elctrokinetic chromatography to improve the separation [24][25][26].…”

Dynamically coated silica monolith with ionic liquids for capillary electrochromatography

“…The application of IL in analytical chemistry has also attracted considerable attention, such as microextraction [22], sensors [23], MALDI-MS [24], chromatography [25], and so on. Until recently, several research groups have reported the utility of IL as buffer modifiers, BGE and dynamic coating agent in CE to achieve better selectivities [26][27][28][29][30]. As wall permanent coating materials, their use for CEC was extensively investigated for the separation and determination of metal cations [31,32], Sildenafil metabolites [33], DNA [34] and alkylphosphonic acids/monoesters [35] etc.…”