Ionic Liquids as Modifiers of Chromatographic and Electrophoretic Systems

Карцова, Л. А.; Бессонова, Е. А.; Колобова, Е. А.

doi:10.1134/s1061934816020064

Cited by 32 publications

(9 citation statements)

References 170 publications

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“…The influences of column temperature (20,25,30,35 and 40 • C) on the retention times of the two anions were investigated under the chromatographic conditions described as Section 2.3. At different temperatures, the Vant Hoff curve is ln k = -ΔH/RT + ΔS/R + ln φ (k is retention factor, T is thermodynamic temperature, ΔH and ΔS are free enthalpy changes and free entropy changes, R is the molar gas constant, φ is two phase volume ratio).…”

Section: Effect Of Column Temperaturementioning

confidence: 99%

“…The unique properties of ILs result in wide use in the fields of organic synthesis [1][2][3], catalysis [3,4], electrochemistry [5,6], nanotechnology [7], and analytical chemistry [8][9][10][11]. In recent years, the applications of ILs in the fields of GC stationary phases [12], LC stationary phases [13][14][15][16][17][18] and mobile phase additives [19,20] have received increasing attention. There are some reports on the analysis of organic substances such as alkaloids [21][22][23][24][25] and metal ions [26][27][28] by using ionic liquids as mobile phase additives, but there are few reports on the analysis of anions [29,30] which needs to be further studied extensively.…”

Section: Introductionmentioning

confidence: 99%

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Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Cui

2019

J of Separation Science

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An analytical method was developed for the simultaneous determination of thiocyanate and iodide by reversed‐phase liquid chromatography with UV detection using imidazolium ionic liquids as mobile phase additives. The chromatographic behaviors of the two anions on a C18 column were studied and compared with four types of reagents including imidazolium ionic liquids, pyridinium ionic liquids, 4‐aminophenol hydrochloride and tetrabutylammonium as mobile phase additives. The effects of the concentrations of imidazolium ionic liquids, organic solvents and detection wavelength on separation and detection of the anions were investigated. The role of ionic liquids, retention rules and mechanisms were discussed. The separation of the anions was performed on the C18 reserved‐phase column using acetonitrile‐0.3 mmol/L 1‐amyl‐3‐methylimidazolium tetrafluoroborate (10:90, v/v) as mobile phase, with column temperature of 35°C, flow rate of 1 mL/min and detection wavelength of 210 nm. Under these conditions, the two anions can be completely separated within 6 min. The limits of detection were 0.05 mg/L. The method was applied for the determination of thiocyanate and iodide in ionic liquid samples and iodide drugs, and the spiked recoveries ranged from 97 to 101%. The method is simple, accurate and meets the requirements of quantitative analysis for thiocyanate and iodide.

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Section: Effect Of Column Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Cui

2019

J of Separation Science

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“…ILs can be used like ion-pair reagents due to the miscibility with water [63][64][65][66][67][68]. Imidazolium-based ILs have been used as mobile phase additives [67] and modifiers [68]. ILs were also used as a silanol suppressor to eliminate the silanol effect that causes tailing of basic compounds on silica-based packing materials.…”

Section: Typical Structures Of Bonded-phase For Hilicmentioning

confidence: 99%

Fundamental Properties of Packing Materials for Liquid Chromatography

Hanai¹

2019

Separations

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The high performance of chemically-modified silica gel packing materials is based on the utilization of pure silica gels. Earlier silica gels used to be made from inorganic silica; however, nowadays, silica gels are made from organic silanes. The surface smoothness and lack of trace metals of new silica gels permits easy surface modifications (chemical reactions) and improves the reproducibility and stability. Sharpening peak symmetry is based on developing better surface modification methods (silylation). Typical examples can be found in the chromatography of amitriptyline for silanol testing and that of quinizarin for trace metal testing. These test compounds were selected and demonstrated sensitive results in the measurement of trace amounts of either silanol or trace metals. Here, we demonstrate the three-dimensional model chemical structures of bonded-phase silica gels with surface electron density for easy understanding of the molecular interaction sites with analytes. Furthermore, a quantitative explanation of hydrophilic and hydrophobic liquid chromatographies was provided. The synthesis methods of superficially porous silica gels and their modified products were introduced.

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“…In particular, there is an increasing interest in the use of these compounds in extraction and separation techniques . Regarding separation techniques, they have been widely used in GC, LC and CE, mainly as stationary phases, additives in mobile phase and modifiers of background electrolytes .…”

Section: Introductionmentioning

confidence: 99%

“…ILs are organic salts with melting points below 100°C or usually closer to room temperature. They are formed by bulky organic cations (pyridinium, pyrrolidinium, imidazolium, tetra‐alkylammonium) and organic (triflate, bistrifluoromethanesulfonimide) or inorganic (chloride, bromide, hexafluorophosphate) anions . The ability to interchange different anions and cations results in multiple combinations of ILs.…”

Section: Introductionmentioning

confidence: 99%

Nuclear magnetic resonance to study the interactions acting in the enantiomeric separation of homocysteine by capillary electrophoresis with a dual system of γ‐cyclodextrin and the chiral ionic liquid EtCholNTf₂

et al. 2019

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The enantiomeric separation of 9‐fluorenylmethoxycarbonyl chloride (FMOC)‐homocysteine (Hcy) by CE was investigated using γ‐CD and the chiral ionic liquid (R)‐(1‐hydroxybutan‐2‐yl)(trimethyl)azanium‐bis(trifluoromethanesulfon)imidate (also called (R)‐N,N,N‐trimethyl‐2‐aminobutanol‐bis(trifluoromethane‐sulfon)imidate) (EtCholNTf2) as chiral selectors. Using 2 mM γ‐CD and 5 mM EtCholNTf2 in 50 mM borate buffer (pH 9), FMOC‐Hcy enantiomers were separated with a resolution value of 3.8. A reversal in the enantiomer migration order in comparison with the single use of γ‐CD in the separation buffer was obtained. Then, NMR experiments were carried out to elucidate the interactions taking place in the enantiomeric separation of FMOC‐Hcy. NMR analyses highlighted the formation of an inclusion complex since the hydrophobic group of FMOC‐Hcy was inserted into the γ‐CD cavity. Moreover, interactions between EtCholNTf2 and γ‐CD were also observed, suggesting that the chiral ionic liquid would also enter the cavity of the γ‐CD.

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Ionic Liquids as Modifiers of Chromatographic and Electrophoretic Systems

Cited by 32 publications

References 170 publications

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Fundamental Properties of Packing Materials for Liquid Chromatography

Nuclear magnetic resonance to study the interactions acting in the enantiomeric separation of homocysteine by capillary electrophoresis with a dual system of γ‐cyclodextrin and the chiral ionic liquid EtCholNTf₂

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Ionic Liquids as Modifiers of Chromatographic and Electrophoretic Systems

Cited by 32 publications

References 170 publications

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Fundamental Properties of Packing Materials for Liquid Chromatography

Nuclear magnetic resonance to study the interactions acting in the enantiomeric separation of homocysteine by capillary electrophoresis with a dual system of γ‐cyclodextrin and the chiral ionic liquid EtCholNTf2

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Nuclear magnetic resonance to study the interactions acting in the enantiomeric separation of homocysteine by capillary electrophoresis with a dual system of γ‐cyclodextrin and the chiral ionic liquid EtCholNTf₂