Solid-phase extraction of room-temperature imidazolium ionic liquids from aqueous environmental samples (original) (raw)
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International Journal of Molecular Sciences, 2006
Interest in ionic liquids for their potential in different chemical processes is constantly increasing, as they are claimed to be environmentally benign -excellent, nonvolatile solvents for a wide range of applications. The wide applicability of these compounds also demands reliable, relatively simple and reproducible analytical techniques. These methods must be applicable not only to different technical or natural matrices but also to the very low concentrations that are likely to be present in biological and environmental systems. In this review, therefore, methods for separating and analysing imidazolium-and pyridinium-type ionic liquids in aqueous matrices using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) are examined. The techniques for identifying ionic liquids are meant primarily to track the concentrations of ionic liquids as residues not only in products and wastes but also in biological or environmental samples. The application of hyphenated techniques in this field is intended to selectively separate the quaternary entity from other cationic and non-ionic species present in the matrix, and to enable its fine-scale quantification. Nowadays, methods developed for cation analysis are based mostly on reversed-phase high-performance liquid chromatography, ion chromatography, ion-pair chromatography and capillary electrophoresis, where various buffered mobile phases are used.
Capillary electrophoretic separation of cationic constituents of imidazolium ionic liquids
ELECTROPHORESIS, 2004
A capillary electrophoretic method for resolving selected imidazolium ionic liquid cations is reported. The method, in which citric buffer is used as the running electrolyte, is simple and reproducible. The separation of a standard mixture is in linear accordance with the relative molecular mass (M r ) of solutes regardless of the type of substitution (alkyl or aryl). The theoretical prediction of compounds as yet not analyzed is therefore possible; however, cations with identical molecular masses are inseparable with this method. Nevertheless, the method's quantitative analytical performance was excellent. The paper also discusses the applicability of a method for tracking the photodegradation kinetics of an exemplary ionic liquid.
Ionic Liquids: Recent Journey Through Chromatographic Separation
Journal of Advanced Scientific Research
Ionic liquids (ILs), despite some of their crucial disadvantages, have been established to be the apt and relevant replacement of the volatile organic compounds (VOCs) in the industrial and academic sectors as solvents. Recent investigations on thriving multifaceted applications of ionic liquids have unleashed that they are really among beneficial “environmentally-benign” solvents as far as their impact on the ecosystem is concerned. This caused them to be an exciting and lucrative domain to explore in a wider fashion and many of the leading research groups are involved in the manifestation of their inherent undisclosed legacy. While exploring the efficacy of ILs, it was found that ILs or IL-based mixed solvent systems were very good alternative of conventional solvents and could act as mobile/stationary phases or additives in gas chromatography (GC), multidimensional gas chromatography (MDGC), inverse gas chromatography (IGC), high performance liquid chromatography (HPLC) and capil...
The present work focussed on application of the environmental friendly 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([BMIM] + [Tf 2 N] − ) ionic liquid for the separations of (alkane/aromatic), (alkane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol) using gas-liquid chromatography (GLC) technique. In this reason the activity coefficients at infinite dilution, γ 13 ∞ , for 31 organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatics, alkanol and ketones) and water in ionic liquid were measured at temperatures of (323.15, 333.15, 343.15, 353.15 and 363.15) K. Stationary phase loadings of (42.83 and 68.66) % by mass were used to ensure repeatability of measurements. Density and viscosity values were measured to confirm the purity of ionic liquid. Partial molar excess enthalpies at infinite dilution, ΔH 1 E,∞
Journal of Chromatography A, 2008
Three ionic liquid (IL)-based aggregates, 1-hexadecyl-3-methylimidazolium bromide (HDMIm-Br), 1-hexadecyl-3-butylimidazolium bromide (HDBIm-Br), and 1,3-didodecylimidazolium bromide (DDDDIm-Br) have been applied to the development of a quantitative solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) method. A sensitivity factor (SF) is defined and introduced for the first time to quantitatively compare the efficiency of the IL-based aggregates by SPME-GC-MS and to evaluate the partitioning strength of several polycyclic aromatic hydrocarbons (PAHs) to the three IL-aggregates. The ILs HDBIm-Br and HDMIm-Br have been used successfully to extract seven PAHs from the certified reference sediment BCR-535 using focused microwave-assisted extraction followed by SPME-GC-MS. Average recoveries for six of the seven certified PAHs were 84.6% for HDMIm-Br and 101% for HDBIm-Br, with relative standard deviation values (RSDs) lower than 19%. The overall extraction method requires short extraction times (around 7 min for the microwave step) and avoids the use of organic solvents.
Advanced Synthesis & Catalysis, 2006
The reaction of N-alkylimidazole with alkyl sulfonates at room temperature affords 1,3-dialkylimidazolium alkanesulfonates as crystalline solids in high yields. The alkanesulfonate anions can be easily substituted by a series of other anions [BF 4 , PF 6 , PF 3 (CF 2 CF 3 ) 3 , CF 3 SO 3 and N(CF 3 SO 2 ) 2 ] by simple reaction of anions, salts, or acids in water at room temperature. Extraction with dichloromethane, filtration through a short basic alumina column and solvent evaporation affords the desired ionic liquids in 80 -95% yield. The purity ( > 99.4%) of these ionic liquids can be determined by 1 H NMR spectra using the intensity of the 13 C satellites of the imidazolium N-methyl group as internal standard.
Isotachophoretic separation of selected imidazolium ionic liquids
Talanta, 2008
Results of determination of selected imidazolium ionic liquids by isotachophoresis (ITP) with conductometric detection was presented. The effects of the molar mass of different ionic liquids on electrophoretic mobility was observed. The presented method was validated and basic validation parameters were determined. Limit of detection (LOD) in a 10 and 25 ng/L for anions and cations, respectively, is very satisfied. Thanks to its low cost and high rate, the presented method can be used in qualitative routine analysis as an alternative technique to liquid chromatography.
ARTICLE IN PRESS Isotachophoretic separation of selected imidazolium ionic liquids 3
Results of determination of selected imidazolium ionic liquids by isotachophoresis (ITP) with conductometric detection was presented. The effects of the molar mass of different ionic liquids on electrophoretic mobility was observed. The presented method was validated and basic validation parameters were determined. Limit of detection (LOD) in a 10 and 25 ng/L for anions and cations, respectively, is very satisfied. Thanks to its low cost and high rate, the presented method can be used in qualitative routine analysis as an alternative technique to liquid chromatography. 9 10 11 12
Journal of Separation Science, 2012
Two imidazolium supported ionic liquid phases (SILPs) containing different anions, trifluoromethanesulphonate [CF 3 SO 3 − ], and tetrafluoroborate [BF 4 − ], were synthesized and evaluated as solid-phase extraction sorbents for extracting acidic pharmaceuticals from aqueous samples under strong anion-exchange conditions, which include an effective cleanup of the sample. The best SILP material [MI + ][CF 3 SO 3 − ] was selected and successfully applied to the determination of acidic pharmaceuticals in different types of water samples (river water and effluent wastewater). The results were then compared to the previously synthesized SILP material based on [MI + ][CF 3 COO − ] and the commercially available Oasis MAX sorbent.