Utility of ionic liquids in analytical separations.

Ionic liquids (ILs), as separation media, have made significant contributions in the past decades in advancing research in gas chromatography (GC), liquid chromatography (LC), and capillary electrophoresis (CE). This review, covering reports published from the mid 1980s to early 2007, shows how ILs have been used so far in separation science, originally primarily as GC stationary phases and later as mobile phase additives (both millimolar and major percent levels) for LC and CE. Representative GC and LC chromatograms as well as CE electropherograms are shown. In addition, the very recent findings on the development of ionic liquids with surfactant properties and its applications for chiral and achiral analysis are discussed.

[1]  Ming-Lan Ge,et al.  Activity Coefficients at Infinite Dilution of Alkanes, Alkenes, and Alkyl Benzenes in 1-Butyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography , 2007 .

[2]  D. Villemin,et al.  Evaluation of chiral ionic liquids as additives to cyclodextrins for enantiomeric separations by capillary electrophoresis. , 2007, Journal of chromatography. A.

[3]  Y. Arai,et al.  Measurement of infinite dilution activity coefficients of n-alkanes in 4-methyl-n-butylpyridinium tetrafluoroborate using gas-liquid chromatography , 2007 .

[4]  Yannis-Nicolas François,et al.  Nonaqueous capillary electrophoretic behavior of 2-aryl propionic acids in the presence of an achiral ionic liquid. A chemometric approach. , 2007, Journal of chromatography. A.

[5]  Bryan M. Hunter,et al.  Alkylammonium Formate Ionic Liquids as Organic Mobile Phase Replacements for Reversed‐Phase Liquid Chromatography , 2007 .

[6]  K. Row,et al.  Separation of Guanine and Hypoxanthine with Some Ionic Liquids in RP-HPLC , 2006 .

[7]  Shai Kendler,et al.  Rapid determination of complex mixtures by dual-column gas chromatography with a novel stationary phase combination and spectrometric detection. , 2006, Journal of chromatography. A.

[8]  E. Wang,et al.  The use of CE‐electrochemiluminescence with ionic liquid for the determination of bioactive constituents in Chinese traditional medicine , 2006, Electrophoresis.

[9]  K. Row,et al.  Retention factors and resolutions of amino benzoic acid isomers with some lonic liquids , 2006 .

[10]  N. Danielson,et al.  Ethylammonium formate as an organic solvent replacement for ion-pair reversed-phase liquid chromatography. , 2006, Journal of chromatographic science.

[11]  Vincent P. Schnee,et al.  Electrokinetic chromatographic characterization of novel pseudo‐phases based on N‐alkyl‐N‐methylpyrrolidinium ionic liquid type surfactants , 2006, Electrophoresis.

[12]  T. Jiang,et al.  Dynamic coating of a capillary with room-temperature ionic liquids for the separation of amino acids and acid drugs by capillary electrophoresis , 2006 .

[13]  S. Verevkin,et al.  Experimental Study of Thermodynamic Properties of Mixtures Containing Ionic Liquid 1-Ethyl-3-methylimidazolium Ethyl Sulfate Using Gas−Liquid Chromatography and Transpiration Method , 2006 .

[14]  S. A. Rizvi,et al.  Synthesis, characterization, and application of chiral ionic liquids and their polymers in micellar electrokinetic chromatography. , 2006, Analytical chemistry.

[15]  Xingguo Qi The Capillary Electrophoresis Based on Ionic Liquids , 2006 .

[16]  A. Stalcup,et al.  Mobile phase effects on retention on a new butylimidazolium-based high-performance liquid chromatographic stationary phase. , 2006, Journal of chromatography. A.

[17]  L. Nie,et al.  Determination of octopamine, synephrine and tyramine in Citrus herbs by ionic liquid improved 'green' chromatography. , 2006, Journal of chromatography. A.

[18]  Kyung Ho Row,et al.  Effect of Concentration of Ionic Liquid 1‐Butyl‐3‐Methylimidazolium, Tetrafuoroborate, for Retention and Separation of Some Amino and Nucleic Acids , 2006 .

[19]  A. Berthod,et al.  Ionic liquids versus triethylamine as mobile phase additives in the analysis of beta-blockers. , 2006, Journal of chromatography. A.

[20]  A. Wells,et al.  On the Freshwater Ecotoxicity and Biodegradation Properties of Some Common Ionic Liquids , 2006 .

[21]  Xingguo Chen,et al.  High Electric Field Strengths in Micellar Electrokinetic Capillary Electrophoresis with Ionic Liquids as Modifiers , 2006 .

[22]  L. Yuan,et al.  (R)‐N,N,N‐Trimethyl‐2‐Aminobutanol‐Bis(Trifluoromethane‐Sulfon)Imidate Chiral Ionic Liquid Used as Chiral Selector in HPCE, HPLC, and CGC , 2006 .

[23]  D. Armstrong,et al.  Determination of solute partition behavior with room-temperature ionic liquid based micellar gas-liquid chromatography stationary phases using the pseudophase model. , 2006, Journal of chromatography. A.

[24]  R. Kaliszan,et al.  Separation of nicotinic acid and its structural isomers using 1-ethyl-3-methylimidazolium ionic liquid as a buffer additive by capillary electrophoresis. , 2006, Journal of pharmaceutical and biomedical analysis.

[25]  Xingguo Chen,et al.  Simultaneous determination of bioactive flavone derivatives in Chinese herb extraction by capillary electrophoresis used different electrolyte systems--borate and ionic liquids. , 2006, Journal of chromatography. A.

[26]  N. Danielson,et al.  Comparison of ethylammonium formate to methanol as a mobile-phase modifier for reversed-phase liquid chromatography. , 2006, Journal of separation science.

[27]  Xingguo Chen,et al.  Rapid separation and determination of aconitine alkaloids in traditional Chinese herbs by capillary electrophoresis using 1-butyl-3-methylimidazoium-based ionic liquid as running electrolyte. , 2006, Biomedical chromatography : BMC.

[28]  Y. Koo,et al.  Application of ionic liquids as mobile phase modifier in HPLC , 2006 .

[29]  Yan-Ping Shi,et al.  Application of 1-alkyl-3-methylimidazolium-based ionic liquids in separation of bioactive flavonoids by capillary zone electrophoresis. , 2006, Journal of separation science.

[30]  S. Pandey Analytical applications of room-temperature ionic liquids: a review of recent efforts. , 2006, Analytica chimica acta.

[31]  Javid Safarov,et al.  Thermodynamic Properties of Mixtures Containing Ionic Liquids. 9. Activity Coefficients at Infinite Dilution of Hydrocarbons, Alcohols, Esters, and Aldehydes in Trimethyl-butylammonium Bis(trifluoromethylsulfonyl) Imide Using Gas−Liquid Chromatography and Static Method , 2006 .

[32]  M. Lahtinen,et al.  A new ionic liquid dimethyldinonylammonium bromide as a flow modifier for the simultaneous determination of eight carboxylates by capillary electrophoresis. , 2005, Journal of chromatography. A.

[33]  S. P. Porras,et al.  Are the asserted advantages of organic solvents in capillary electrophoresis real? A critical discussion , 2005, Electrophoresis.

[34]  D. Armstrong,et al.  Immobilized ionic liquids as high-selectivity/high-temperature/high-stability gas chromatography stationary phases. , 2005, Analytical chemistry.

[35]  R. Kaliszan,et al.  Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids , 2005 .

[36]  Sam F. Y. Li,et al.  Ionic liquids as additives for separation of benzoic acid and chlorophenoxy acid herbicides by capillary electrophoresis , 2005 .

[37]  J. Planeta,et al.  Solute partitioning between the ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate and supercritical CO2 from capillary-column chromatography. , 2005, The journal of physical chemistry. B.

[38]  S. Verevkin,et al.  Thermodynamic Properties of Mixtures Containing Ionic Liquids. 6. Activity Coefficients at Infinite Dilution of Hydrocarbons, Alcohols, Esters, and Aldehydes in 1-Methyl-3-octyl-imidazolium Tetrafluoroborate Using Gas−Liquid Chromatography , 2005 .

[39]  S. Verevkin,et al.  Thermodynamic Properties of Mixtures Containing Ionic Liquids. 8. Activity Coefficients at Infinite Dilution of Hydrocarbons, Alcohols, Esters, and Aldehydes in 1-Hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl) Imide Using Gas-Liquid Chromatography , 2005 .

[40]  Sheila N. Baker,et al.  An analytical view of ionic liquids. , 2005, The Analyst.

[41]  A. Berthod,et al.  Nonmolecular solvents in separation methods: dual nature of room temperature ionic liquids. , 2005, Analytical chemistry.

[42]  C. E. Evans,et al.  Retention characteristics of a new butylimidazolium-based stationary phase , 2005, Analytical and bioanalytical chemistry.

[43]  Xingguo Chen,et al.  Rapid and sensitive determination of anthraquinones in Chinese herb using 1-butyl-3-methylimidazolium-based ionic liquid with beta-cyclodextrin as modifier in capillary zone electrophoresis. , 2004, Journal of chromatography. A.

[44]  T. Welton,et al.  Chiral ionic liquids as stationary phases in gas chromatography. , 2004, Analytical chemistry.

[45]  Sam F. Y. Li,et al.  Determination of ammonium and metal ions by capillary electrophoresis-potential gradient detection using ionic liquid as background electrolyte and covalent coating reagent. , 2004, Journal of chromatography. A.

[46]  Liu Xia,et al.  Ionic liquids as additives in high performance liquid chromatography: Analysis of amines and the interaction mechanism of ionic liquids , 2004 .

[47]  J. Planeta,et al.  Partition coefficients of low-volatility solutes in the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate-supercritical CO2system from chromatographic retention measurements , 2004 .

[48]  C. Poole Chromatographic and spectroscopic methods for the determination of solvent properties of room temperature ionic liquids. , 2004, Journal of chromatography. A.

[49]  R. Kaliszan,et al.  Suppression of deleterious effects of free silanols in liquid chromatography by imidazolium tetrafluoroborate ionic liquids. , 2004, Journal of chromatography. A.

[50]  A. Stalcup,et al.  Ionic Liquids in Chromatography and Capillary Electrophoresis , 2004 .

[51]  Sam F. Y. Li,et al.  Electrophoresis of DNA in ionic liquid coated capillary. , 2003, The Analyst.

[52]  I. Warner,et al.  Separation of achiral and chiral analytes using polymeric surfactants with ionic liquids as modifiers in micellar electrokinetic chromatography. , 2003, Analytical chemistry.

[53]  D. Armstrong,et al.  High-stability ionic liquids. A new class of stationary phases for gas chromatography. , 2003, Analytical chemistry.

[54]  A. Stalcup,et al.  Capillary electrophoretic and nuclear magnetic resonance studies of interactions between halophenols and ionic liquid or tetraalkylammonium cations. , 2003, Journal of chromatography. A.

[55]  Liang Zhao,et al.  Effect of 1-alkyl-3-methylimidazolium-based ionic liquids as the eluent on the separation of ephedrines by liquid chromatography. , 2003, Journal of chromatography. A.

[56]  T. Jiang,et al.  Dynamically coating the capillary with 1-alkyl-3-methylimidazolium-based ionic liquids for separation of basic proteins by capillary electrophoresis , 2003 .

[57]  Sam F. Y. Li,et al.  1,3-dialkylimidazolium-based room-temperature ionic liquids as background electrolyte and coating material in aqueous capillary electrophoresis. , 2003, Journal of chromatography. A.

[58]  Lijun He,et al.  Effect of Ionic Liquids as Mobile Phase Additives on Retention of Catecholamines in Reversed-Phase High-Performance Liquid Chromatography , 2003 .

[59]  M. Vaher,et al.  Application of 1-alkyl-3-methylimidazolium-based ionic liquids in non-aqueous capillary electrophoresis. , 2002, Journal of chromatography. A.

[60]  Sam F. Y. Li,et al.  An ionic liquid coating for determination of sildenafil and UK‐103,320 in human serum by capillary zone electrophoresis‐ion trap mass spectrometry , 2002, Electrophoresis.

[61]  T. Welton,et al.  Characterizing ionic liquids on the basis of multiple solvation interactions. , 2002, Journal of the American Chemical Society.

[62]  I. Warner,et al.  Enantiomeric separations using poly(L-valine) and poly(L-leucine) surfactants. Investigation of steric factors near the chiral center. , 2002, Journal of chromatography. A.

[63]  A. Kulikov,et al.  Thermodynamic Properties of Mixtures Containing Ionic Liquids. 2. Activity Coefficients at Infinite Dilution of Hydrocarbons and Polar Solutes in 1-Methyl-3-ethyl-imidazolium Bis(trifluoromethyl-sulfonyl) Amide and in 1,2-Dimethyl-3-ethyl-imidazolium Bis(trifluoromethyl-sulfonyl) Amide Using Gas−Liq , 2002 .

[64]  Merike Vaher,et al.  Ionic liquids as electrolytes for nonaqueous capillary electrophoresis , 2002, Electrophoresis.

[65]  S. Verevkin,et al.  Thermodynamic Properties of Mixtures Containing Ionic Liquids. 1. Activity Coefficients at Infinite Dilution of Alkanes, Alkenes, and Alkylbenzenes in 4-Methyl-n-butylpyridinium Tetrafluoroborate Using Gas−Liquid Chromatography , 2001 .

[66]  A. Stalcup,et al.  Capillary electrophoretic application of 1-alkyl-3-methylimidazolium-based ionic liquids. , 2001, Analytical chemistry.

[67]  D. Armstrong,et al.  Examination of ionic liquids and their interaction with molecules, when used as stationary phases in gas chromatography. , 1999, Analytical chemistry.

[68]  C. Poole,et al.  Gas chromatographic study of the solution thermodynamics of organic solutes in tetraalkylammonium alkanesulfonate and perfluoroalkanesulfonate solvents , 1990 .

[69]  C. Poole,et al.  Changes in retention and polarity accompanying the replacement of hydrogen by fluorine in tetraalkylammonium alkyl- and arylsulfonate salts used as stationary phases in gas chromatography , 1989 .

[70]  C. Poole,et al.  Solute-solvent interactions in liquid tetrabutylammonium sulfonate salts studied by gas chromatography , 1988 .

[71]  K. Furton,et al.  Solute-solvent interactions in liquid alkylammonium 4-toluenesulfonate salts studied by gas chromatography , 1987 .

[72]  K. Furton,et al.  Liquid Organic Salt Phases for Gas Chromatography , 1986 .

[73]  K. Furton,et al.  Organic salts, liquid at room temperature, as mobile phases in liquid chromatography , 1986 .

[74]  J. Wilkes,et al.  Friedel-Crafts reactions in ambient-temperature molten salts , 1986 .

[75]  C. Poole,et al.  Evaluation of tetraalkylammonium tetrafluoroborate salts as high-temperature stationary phases for packed and open-tubular column gas chromatography , 1985 .

[76]  K. Furton,et al.  Variation in the gas chromatographic stationary phase propertiesof tetra-n-butylammonium salts as a function of the anion type , 1985 .

[77]  C. Poole,et al.  Preparation and properties of open tubular columns coated with tetra-n-butylammonium tetrafluoroborate , 1984 .

[78]  C. Poole,et al.  Survey of organic molten salt phases for gas chromatography , 1984 .

[79]  C. Poole,et al.  MOLTEN ORGANIC SALT PHASE FOR GAS-LIQUID CHROMATOGRAPHY. , 1982 .

[80]  C. Hussey,et al.  Dialkylimidazolium chloroaluminate melts: a new class of room-temperature ionic liquids for electrochemistry, spectroscopy and synthesis , 1982 .

[81]  Qing Zhou,et al.  Activity Coefficients at Infinite Dilution of Polar Solutes in 1-Butyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography , 2007 .

[82]  N. Danielson,et al.  Ethylammonium Acetate as a Mobile Phase Modifier for Reversed Phase Liquid Chromatography , 2005 .

[83]  D. Armstrong,et al.  Ionic liquids as stationary phase solvents for methylated cyclodextrins in gas chromatography , 2001 .

[84]  M. Vaher,et al.  Non-aqueous capillary electrophoresis in acetonitrile using lonic-liquid buffer electrolytes , 2001 .

[85]  A. Stalcup,et al.  Tetraethylammonium tetrafluoroborate: a novel electrolyte with a unique role in the capillary electrophoretic separation of polyphenols found in grape seed extracts. , 2000, The Analyst.

[86]  Michael J. Zaworotko,et al.  Air and water stable 1-ethyl-3-methylimidazolium based ionic liquids , 1992 .

[87]  C. Poole,et al.  Applications of ethylammonium and propylammonium nitrate solvents in liquid-liquid extraction and chromatography , 1990 .

[88]  Y. Chauvin,et al.  Catalytic dimerization of alkenes by nickel complexes in organochloroaluminate molten salts , 1990 .

[89]  C. Poole,et al.  Chromatographic and spectroscopic studies of the solvent properties of a new series of room-temperature liquid tetraalkylammonium sulfonates , 1989 .

[90]  C. Poole,et al.  Solute—solvent interactions in tetra-n-butylphosphonium salts studied by gas chromatography , 1988 .

[91]  C. Poole,et al.  Chemical interactions as a possible limitation on the useful solvent properties of liquid alkylammonium salts , 1988 .

[92]  K. Furton,et al.  Correlation of solute retention in gas chromatography with properties of the anion for tetra-n-butylammonium salts , 1987 .

[93]  K. Furton,et al.  Thermodynamic characteristics of solute—solvent interactions in liquid organic salt solvents, studied by gas chromatography , 1987 .

[94]  C. Poole,et al.  Solvent properties of liquid organic salts used as mobile phases in microcolumn reversed-phase liquid chromatography , 1987 .

[95]  K. Furton,et al.  Synthesis and gas chromatographic stationary phase properties of alkylammonium thiocyanates , 1986 .

[96]  C. Poole,et al.  Influence of phase loading on the performance of whisker-walled open tubular columns coated with organic molten salts , 1985 .