Ionic liquids: solvents and sorbents in sample preparation

Abstract

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. K E Y W O R D Salternative solvents, ionic liquids, magnetic ionic liquids, microextraction, sample preparation

Alternative Green Extraction Phases Applied to Microextraction Techniques for Organic Compound Determination

“…ILs have been successfully applied to the liquid phase microextraction technique (LPME) as a less toxic alternative to conventional organic solvents. Considering these most notable properties, the potential usage of ILs as the extraction phase for LPME and applications has already been extensively reviewed by different authors [31][32][33][34][35]. The successful use of ILs in extraction phases is related to their structure.…”

Critical evaluation of microextraction pretreatment techniques – Part 1: Single drop and sorbent‐based techniques

“…ILs exhibit “structural tunability”, i.e. their viscosity and surface tension can be easily tuned and manipulated to make them less volatile and to form larger and stable microdrops (greater viscosities), which adhere more strongly to the needle and therefore can be used at elevated extraction temperatures . Their disadvantage is poor compatibility with direct injection into a GC (modification of the injection inlet is needed ) and questionable toxicity and biodegradability.…”

Ionic liquid‐mediated aqueous two‐phase system to enhance the partitioning of lignin

“…During the past decade, its application has been extended to include the separation of various components such as cells, membranes, viruses, proteins, nucleic acids, enzymes, etc . However, ATPSs comprising inorganic salts and polymers encounter several limitations that prevent this process from keeping‐up with the challenging demands of selectivity and sensitivity during the process . During the past decade, ILs have been used as an effective solvent for extracting lignin from lignocelluloses .…”