Use of 1-alkyl-3-methylimidazolium-based ionic liquids as background electrolytes in capillary electrophoresis for the analysis of inorganic anions

Ionic Liquids in Capillary Electrophoresis

Recently, a great interest was drawn toward ionic liquids (ILs) in analytical separation techniques. ILs possess many properties making them excellent additives in capillary electrophoresis (CE) background electrolytes (BGE). The most important property is the charge of the dissolved ions in BGE enabling the cations to interact with deprotonated silanol groups on the capillary surface and thereby modifying the electroosmotic flow (EOF). Ionic and/or proton donor-acceptor interactions between analyte and IL are possible interactions facilitating new kinds of separation mechanisms in CE. Further advantages of ILs are the high conductivity, the environmentally friendliness, and the good solubility for organic and inorganic compounds. The most commonly used ILs in capillary electrophoresis are dialkylimidazolium-based ILs, whereas for enantioseparation a lot of innovative chiral cations and anions were investigated.ILs are reported to be additives to a normal CE background electrolyte or the sole electrolyte in CE, nonaqueous CE (NACE), micellar electrokinetic chromatography (MEKC), and in enantioseparation. An overview of applications and separation mechanisms reported in the literature is given here, in addition to the enantioseparation of pseudoephedrine using tetrabutylammonium chloride (TBAC) as IL additive to an ammonium formate buffer containing β-cyclodextrin (β-CD).

Impact of ionic liquids in environment and humans: An overview

Ionic liquids enclose a large number of molecular structures consisting of a cation and an anion. Their physical state and their chemical properties can be tuned by different combination of the ions and a large number of ionic liquids have already been reported. Toxicity of ionic liquids is a subject of great importance concerning their likely use as greener solvents and new materials for a broad number of potential applications. This review provides relevant toxicological data published so far about this topic and includes a large range of ionic liquids based on different cations (imidazolium, pyridinium, pyrrolidinium, quaternary ammonium, quaternary phosphonium and guanidinium) and anions (halogens-Br, Cl, bis (trifluoromethyl)sulfonylamide, tetrafluoroborate, hexafluorophosphate, dicyanamide, acesulfame and saccharin, amongst others). In general, toxicity of ionic liquids depends on both ions and the effect of the cation alkyl chain length is very pronounced although the type of anion also exerts impact on the overall toxicity.