Ionic liquids in analytical chemistry

Sun, Ping; Armstrong, Daniel W.

doi:10.1016/j.aca.2009.12.007

Cited by 668 publications

(348 citation statements)

References 224 publications

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“…Neat ionic liquids (ILs) have been studied extensively since they are promising candidates for different applications,1 e. g. in the fields of catalysis,2, 3, 4 fuel cells,5,6 lithium ion batteries,7, 8, 9 solvents,10,11 lubricants,12,13 sensors,14,15 and gas separation technologies,15, 16, 17 to name only a few. In many of these applications, the surface of the IL plays a decisive role, because it is its interface to the environment.…”

Section: Introductionmentioning

confidence: 99%

Surface Enrichment in Equimolar Mixtures of Non‐Functionalized and Functionalized Imidazolium‐Based Ionic Liquids

et al. 2018

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For equimolar mixtures of ionic liquids with imidazolium‐based cations of very different electronic structure, we observe very pronounced surface enrichment effects by angle‐resolved X‐ray photoelectron spectroscopy (XPS). For a mixture with the same anion, that is, 1‐methyl‐3‐octylimidazolium hexafluorophosphate+1,3‐di(methoxy)imidazolium hexafluorophosphate ([C8C1Im][PF6]+[(MeO)2Im][PF6]), we find a strong enrichment of the octyl chain‐containing [C8C1Im]+ cation and a corresponding depletion of the [(MeO)2Im]+ cation in the topmost layer. For a mixture with different cations and anions, that is, [C8C1Im][Tf2N]+[(MeO)2Im][PF6], we find both surface enrichment of the [C8C1Im]+ cation and the [Tf2N]− (bis[(trifluoromethyl)sulfonyl]imide) anion, while [(MeO)2Im]+ and [PF6]− are depleted from the surface. We propose that the observed behavior in these mixtures is due to a lowering of the surface tension by the enriched components. Interestingly, we observe pronounced differences in the chemical shifts of the imidazolium ring signals of the [(MeO)2Im]+ cations as compared to the non‐functionalized cations. Calculations of the electronic structure and the intramolecular partial charge distribution of the cations contribute to interpreting these shifts for the two different cations.

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Section: Introductionmentioning

confidence: 99%

Surface Enrichment in Equimolar Mixtures of Non‐Functionalized and Functionalized Imidazolium‐Based Ionic Liquids

et al. 2018

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“…Although classical organic solvents have traditionally been used as extractants in LPME techniques, the use of ionic liquids (ILs) has recently attracted interest as a promising alternative [4]. ILs are melted salts at room temperature that possess unique properties among which we can highlight their high thermal and chemical stability with negligible vapour pressure, tuneable viscosity, electrolytic conductivity, wide electrochemical window and good extractability of organic compounds and metal ions [5]. The utilization of ILs has helped to overcome problems associated with LPME techniques using classical organic solvents [4], and enabled the development of new methods such as temperature-controlled IL dispersive liquid-liquid microextraction [6] and in situ IL formation dispersive liquid-liquid microextraction (in situ IL-DLLME) [7,8].…”

Section: Introductionmentioning

confidence: 99%

Tungsten coil atomic emission spectrometry combined with dispersive liquid–liquid microextraction: A synergistic association for chromium determination in water samples

Vidal

Silva

Canals

et al. 2016

Talanta

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A novel and environmentally friendly analytical method is reported for total chromium determination and chromium speciation in water samples, whereby tungsten coil atomic emission spectrometry (WCAES) is combined with in situ ionic liquid formation dispersive liquid-liquid microextraction (in situ IL-DLLME).A two stage multivariate optimization approach has been developed employing a Plackett-Burman design for screening and selection of the significant factor involved in the in situ IL-DLLME procedure, which was later optimized by means were 3 and 10 µg L -1 , respectively. This is a 233-fold improvement when 2 compared with chromium determination by WCAES without using preconcentration. The repeatability of the proposed method was evaluated at two different spiking levels (10 and 50 µg L -1 ) obtaining coefficients of variation of 11.4 and 3.6% (n=3), respectively. A certified reference material (SRM-1643e NIST) was analysed in order to determine the accuracy of the method for total chromium determination and 112.3% and 2.5 µg L -1 were the recovery (trueness) and standard deviation values, respectively. Tap, bottled mineral and natural mineral waters were analysed at 60 µg L -1 spiking level of total Cr content at two Cr(VI)/Cr(III) ratios, and relative recovery values were ranged between 88 and 112% showing that the matrix has a negligible effect. To our knowledge, this is the first time that combines in situ IL-DLLME and WCAES.

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“…During the last two decades, ILs have attracted escalating interest in miscellaneous research genera including synthetic chemistry, separation techniques, engineering fluids, analytical chemistry, and food sciences. Due to their outstanding properties including nonvolatility, high ionic conductivity, and recyclability, these are regarded as greener solvents in comparison to conventional organic solvents (1)(2)(3)(4). Moreover, recently, the possibilities of using ILs in pharmaceutical sciences have been investigated due to their modifiable physicochemical properties like viscosity and polarity, reaction media and catalytic role in active pharmaceutical ingredient (PI) synthesis, and, most importantly, the excellent solubilization ability for hydrophobic and hydrophilic drugs (5)(6)(7)(8)(9).…”

Section: Introductionmentioning

confidence: 99%

Development of Novel Ionic Liquid-Based Microemulsion Formulation for Dermal Delivery of 5-Fluorouracil

et al. 2014

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Abstract. The present study was aimed at synthesizing an imidazole-based ionic liquid 1-butyl-3-methylimidazolium bromide (BMIMBr) and subsequent development of a novel ionic liquid-in-oil (IL/o) microemulsion (ME) system for dermal delivery of a poorly permeating drug 5-fluorouracil (5-FU). A significant enhancement in the solubility of 5-FU was observed in BMIMBr. IL/o MEs of 5-FU were prepared using isopropyl myristate, Tween 80/Span 20, and BMIMBr. Results of ex vivo skin permeation studies through mice skin indicated that the selected IL/o ME exhibited 4-fold enhancement in percent drug permeation as compared to aqueous solution, 2.3-fold as compared to hydrophilic ointment, and 1.6-fold greater permeation than water in oil (w/o) ME. The results of in vivo studies against dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mice skin carcinogenesis demonstrated that the IL/o ME could effectively treat skin cancer in 4 weeks. In addition, the side effects such as erythema and irritation associated with the conventional formulations were not observed. Histopathological studies showed that the use of IL/o ME caused no anatomic and pathological changes in the skin structure of mice. These studies suggest that the use of IL-based ME system can efficiently enhance the solubility and permeability of 5-FU and hence its therapeutic efficacy.KEY WORDS: 5-fluorouracil; dermal delivery; ionic liquids; ionic liquid in oil (IL/o) microemulsion; skin cancer.

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Ionic liquids in analytical chemistry

Cited by 668 publications

References 224 publications

Surface Enrichment in Equimolar Mixtures of Non‐Functionalized and Functionalized Imidazolium‐Based Ionic Liquids

Surface Enrichment in Equimolar Mixtures of Non‐Functionalized and Functionalized Imidazolium‐Based Ionic Liquids

Tungsten coil atomic emission spectrometry combined with dispersive liquid–liquid microextraction: A synergistic association for chromium determination in water samples

Development of Novel Ionic Liquid-Based Microemulsion Formulation for Dermal Delivery of 5-Fluorouracil

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