An analytical view of ionic liquids

Abstract

Within the last decade, ionic liquids have come to the fore as environmentally-responsible designer solvents. But what are ionic liquids and what can they offer the analytical scientist? This article addresses these questions and chronicles recent progress made in the application of ionic liquids toward analytical problem-solving. While further progress is required before ionic liquids become mainstream analytical solvents, results to date commend their use in various modes of chemical analysis. It is our aim that the findings reported herein draw other researchers into this area and encourage the increased application of ionic liquids in this manner.

Electrospray mass spectral fragmentation study of N,N′-disubstituted imidazolium ionic liquids

“…Due to their low vapor pressure, high thermal stability, ease of recovery facilitating recycling, and applicability to both chemical and enzymatic catalytic processes, ILs have been advocated as reaction media to replace volatile organic solvents (for recent reviews see [1]). Room-temperature ionic liquids have now been explored as media for electrochemical technologies [2], chemical extractions [3], various other industrial processes [4] for analytical purposes [5], and, for example, as matrices in matrixassisted laser desorption ionization [6]. More recently, the use of imidazolium ILs which constitute with pyridinium ILs the two main IL families as soluble supports for organic synthesis to facilitate phase separation and purification has also been demonstrated [7].…”

Thermal Decomposition Behaviors of Imidazolium-type Ionic Liquids Studied by Pyrolysis-Gas Chromatography

“…1 In the field of analytical chemistry, ionic liquids are used as solvents for extraction and spectroscopic measurements, chromatographic stationary phases, matrix reagents for soft laser desorption/ionization mass spectrometry (MS), and electrolytes for electrochemical analysis and electrophoresis. [2][3][4][5][6] Due to not only their inherent ionic nature but also their high thermal stability and low volatility, the ionic liquids also have a potential as a specific media for sample preparation, especially for the thermal decomposition of polymeric materials and natural organic products. For this application, it is important to know the thermal decomposition behaviors of the ionic liquids themselves at elevated temperature.…”

Mutual Solubility of Hydrophobic Ionic Liquids and Water in Liquid-Liquid Two-phase Systems for Analytical Chemistry

“…More than a dozen review articles dealing with the application of ILs to analytical chemistry have appeared in the last five years. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Among many possibilities of applying ionic liquids, IL-water (W) two-phase systems that consist of an aqueous or a nonpolar molecular solvent and an ionic liquid are of considerable relevance with analytical chemistry and separation technology. A direct application of IL-W two-phase systems is the extraction of neutral compounds of relatively low molecular weights, [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] biopolymers 44,[48][49][50][51] and ions.…”