Rapid and sensitive determination of anthraquinones in Chinese herb using 1-butyl-3-methylimidazolium-based ionic liquid with β-cyclodextrin as modifier in capillary zone electrophoresis

Qi, Shengda; Cui, Shuya; Chen, Xingguo; Hu, Zhide

doi:10.1016/j.chroma.2004.09.090

Cited by 105 publications

(51 citation statements)

References 40 publications

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“…For instance, Qi et al used ILs as running electrolytes in capillary zone electrophoresis and b-cyclodextrin as the modifier for the separation of the anthraquinones extract of Chinese herb. [34] The inclusion complexation of methyl orange or phenol with CDs in ILs has been studied by using spectral analyses. [35] CDs or their derivatives dissolved in ILs can be used to prepare stationary phases in gas chromatography.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Gao

et al. 2005

Chemistry A European J

139

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The solubilities of beta-cyclodextrin (beta-CD), ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), and their mixture in water were determined, and the conductivity of these aqueous solutions was measured. It was demonstrated that beta-CD and bmimPF6 could enhance the solubility of each other, and the solubility curves of each were linear with gradients of about 1. The conductivity decreased remarkably with increasing beta-CD concentration, and a discernible break in the conductivity curve could be observed when beta-CD and bmimPF6 were equimolar in the solution. The solubility and conductivity results indicated that inclusion complexes (ICs) of 1:1 stoichiometry were formed. The inclusion compounds were further characterized by using powder X-ray diffraction (XRD) analysis, 13C CP/MAS (cross-polarization magic-angle spinning) NMR and 1H NMR spectroscopy, and thermogravimetric analysis (TGA). The results showed that the ICs were a fine crystalline powder. The host-guest system exhibited a channel-type structure and each glucose unit of beta-CD was in a similar environment. The decomposition temperature of the ICs was lower than that of bmimPF6 and beta-CD individually.

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Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Gao

et al. 2005

Chemistry A European J

139

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“…In this way, Qi et al determined anthraquinones [27] and bioactive flavone derivatives [28] in Chinese herb. On the one hand, separation of anthraquinones [26] was carried out using the combination between bmimBF 4 and CD.…”

Section: Il As Pseudostationary Phase In Ekcmentioning

confidence: 99%

“…Anthraquinones [27] and bioactive flavone derivatives [28] in Chinese herbs, as well as basic proteins [29], amino acids and acid drugs [30], herbicides [31], bioactive flavonoids [32], and nicotinic acid and its isomers [33] have been determined using dialkylimidazolium-based IL as EOF modifiers. In all of these separations, IL have a double role; on the one hand, cations are dissolved in the bulk solutions; and on the other hand, capillary inner surface is covered with cations (see Fig.…”

Section: Il As Chemical Modifiers In Czementioning

confidence: 99%

Ionic liquids and CE combination

et al. 2007

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This paper reviews and discusses the analytical combination of ionic liquids (IL) with CE. On the one hand, it shows CE as a powerful technique to separate impurities from IL as well as being capable to determine physical and chemical properties of IL. On the other hand, it also shows how IL are employed in CE separations to enhance resolution, peak efficiency and peak symmetry. Specifically, IL are used as additives in CZE, NACE, and MEKC and as support coatings of the capillary wall in electrochromatography. The integrity of the IL in the electrophoretic system as well as the roles of the cations and anions of the IL in the electrophoretic separation are also discussed.

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“…The combined use of 1-butyl-3-methylimidazolium tetrafluoroborate (1-B-3-MI-TFB) and b-cyclodedextrin as additives of the electrolyte solution has been reported for the separation of anthraquinones in Chinese herb [28]. Furthermore, dialkylimidazolium-based ionic liquids have been employed in non-aqueous CE for the separation of water-insoluble dyes [29], carboxylic acids and phenols [30].…”

Section: Introductionmentioning

confidence: 99%

Co‐electroosmotic capillary electrophoresis of basic proteins with 1‐alkyl‐3‐methylimidazolium tetrafluoroborate ionic liquids as non‐covalent coating agents of the fused‐silica capillary and additives of the electrolyte solution

2009

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The paper reports the results of a study carried out to evaluate the use of three 1-alkyl-3-methylimidazolium-based ionic liquids as non-covalent coating agents for bare fused-silica capillaries and additives of the electrolyte solutions (BGE) for CE of basic proteins in the co-EOF separation mode. The three ionic liquids are differentiated from each other by the length of the alkyl group on the imidazolium cation, consisting of either an ethyl, butyl or octyl substituent, whereas tetrafluoroborate is the common anionic component of the ionic liquids. Coating the capillary with the ionic liquid resulted in improved peak shape and protein separation, while the EOF was maintained cathodic. This indicates that each ionic liquid is effective at masking the protein interaction sites on the inner surface of the capillary, also when its adsorption onto the capillary wall has not completely neutralized all the negative charges arising from the ionization of the silanol groups and the ionic liquid is not incorporated into the BGE employed for separation. Using the coated capillaries with BGE containing the ionic liquid employed for the coating, at concentration low enough to maintaining the EOF cathodic, both peak shape and protein separation varied to different extents, based on the particular ionic liquid used and its concentration. Fast and efficient separation of the model basic protein mixture in co-electroosmotic CE is obtained with the 1-butyl-3-methylimidazolium tetrafluoroborate coated capillary and 100 mM acetate buffer (pH 4.0) containing 4.4 mM 1-butyl-3-methylimidazolium tetrafluoroborate as the BGE.

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Rapid and sensitive determination of anthraquinones in Chinese herb using 1-butyl-3-methylimidazolium-based ionic liquid with β-cyclodextrin as modifier in capillary zone electrophoresis

Cited by 105 publications

References 40 publications

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Preparation and Characterization of Inclusion Complexes of β‐Cyclodextrin with Ionic Liquid

Ionic liquids and CE combination

Co‐electroosmotic capillary electrophoresis of basic proteins with 1‐alkyl‐3‐methylimidazolium tetrafluoroborate ionic liquids as non‐covalent coating agents of the fused‐silica capillary and additives of the electrolyte solution

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