Modern approaches in dispersive liquid-liquid microextraction (DLLME) based on ionic liquids: A review

Recent advances on ionic liquid uses in separation techniques.

Ionic liquids (ILs) are a highly unique class of non-molecular solvents that possess melting points below 100 ºC.1 ILs that have melting points below room temperature are often referred to as room temperature ionic liquids (RTILs). ILs possess a wide variety of unique physico-chemical properties, including low or negligible vapor pressure at room temperature, high thermal and electrochemical stability, and high conductivity.2.

Advances of Ionic Liquids in Analytical Chemistry.

The ten principles of GSP are presented with the aim of establishing a road map toward the development of overall greener analytical methodologies. Paramount aspects for greening sample preparation and their interconnections are identified and discussed. These include the use of safe solvents/reagents and materials that are renewable, recycled and reusable, minimizing waste generation and energy demand, and enabling high sample throughput, miniaturization, procedure simplification/automation, and operator's safety. Further, the importance of applying green metrics for assessing the greenness of sample preparation methods is highlighted, next to the contribution of GSP in achieving the broader goal of sustainability. Green sample preparation is sample preparation. It is not a new subdiscipline of sample preparation but a guiding principle that promotes sustainable development through the adoption of environmentally benign sample preparation procedures. • The ten principles of green sample preparation are presented. • Sustainability issues on solvents, reagents and materials are considered. • Fast, miniaturized, automated, in situ and low-energy methods are preferred. • Post-sample preparation configuration for analysis is considered. • Green metrics and the impact on sustainable development are discussed. 

The Ten Principles of Green Sample Preparation

The applications of ionic liquids (ILs) and IL-derived sorbents are rapidly expanding. By careful selection of the cation and anion components, the physicochemical properties of ILs can be altered to meet the requirements of specific applications. Reports of IL solvents possessing high selectivity for specific analytes are numerous and continue to motivate the development of new IL-based sample preparation methods that are faster, more selective, and environmentally benign compared to conventional organic solvents. The advantages of ILs have also been exploited in solid/polymer formats in which ordinarily nonspecific sorbents are functionalized with IL moieties in order to impart selectivity for an analyte or analyte class. Furthermore, new ILs that incorporate a paramagnetic component into the IL structure, known as magnetic ionic liquids (MILs), have emerged as useful solvents for bioanalytical applications. In this rapidly changing field, this Review focuses on the applications of ILs and IL-based sorbents in sample preparation with a special emphasis on liquid phase extraction techniques using ILs and MILs, IL-based solid-phase extraction, ILs in mass spectrometry, and biological applications.

Ionic liquids: solvents and sorbents in sample preparation

Magnetic ionic liquids in analytical chemistry: A review

Introducing a new and rapid microextraction approach based on magnetic ionic liquids: Stir bar dispersive liquid microextraction.

Magnetic ionic liquids (MILs) are distinguished from traditional ionic liquids (ILs) by the incorporation of a paramagnetic component within their chemical structure. Hydrophobic MILs are novel solvents that can be used in many applications, including liquid–liquid extraction (LLE) and catalysis. Low viscosity and low water solubility are essential features that determine their feasibility in LLE. In this study, extremely hydrophobic MILs were synthesized by using transition and rare earth metal hexafluoroacetylacetonate chelated anions paired with the trihexyl(tetradecyl)phosphonium ([P66614+]) cation. Hydrophobic MILs exhibiting water solubilities less than 0.01% (v/v) were synthesized in a rapid two-step procedure. Furthermore, the viscosities of the MILs are among some of the lowest ever reported for hydrophobic MILs (276.5–927.9 centipoise (cP) at 23.7 °C) dramatically improving the ease of handling these liquids. For the first time, the magnetic properties of MILs possessing hexafluoroacetylacetonate chelated metal anions synthesized in this study are reported using a superconducting quantum interference device (SQUID) magnetometer. Effective magnetic moments (μeff) as high as 9.7 and 7.7 Bohr magnetons (μB) were achieved by incorporating high spin dysprosium and gadolinium ions, respectively, into the anion component of the MIL. The low viscosity, high hydrophobicity, and large magnetic susceptibility of these MILs make them highly attractive and promising solvents for separations and purification, liquid electrochromic materials, catalytic studies, as well as microfluidic applications.

Synthesis and characterization of low viscosity hexafluoroacetylacetonate-based hydrophobic magnetic ionic liquids

Rapid and sensitive analysis of polychlorinated biphenyls and acrylamide in food samples using ionic liquid-based in situ dispersive liquid-liquid microextraction coupled to headspace gas chromatography.

Stephen A. Pierson

Papers

Magnetic ionic liquids in analytical chemistry: A review

Introducing a new and rapid microextraction approach based on magnetic ionic liquids: Stir bar dispersive liquid microextraction.

Synthesis and characterization of low viscosity hexafluoroacetylacetonate-based hydrophobic magnetic ionic liquids

Rapid and sensitive analysis of polychlorinated biphenyls and acrylamide in food samples using ionic liquid-based in situ dispersive liquid-liquid microextraction coupled to headspace gas chromatography.

Enhanced magnetic ionic liquid-based dispersive liquid-liquid microextraction of triazines and sulfonamides through a one-pot, pH-modulated approach.