Characterization of hexacationic imidazolium ionic liquids as effective and highly stable gas chromatography stationary phases

Abstract

Polycationic ionic liquids (ILs) are an attractive class of ILs with great potential applicability as gas chromatography stationary phases. A family of hexacationic imidazolium ILs derived from the cycloalkanol family was chemically first prepared in a straightforward manner and then applied for analytical separation purposes. Four tuneable engineering vectors, namely cation ring size structure, anion nature, spatial disposition of cycloalkanol substituents and O-substitution, were considered as experimental parameters for the design of the desired ionic liquids. A total number of five new phases based on a common benzene core respectively exhibited column efficiencies around to 2500 plates/m, broad operating temperature ranges and also, even more importantly, good thermal stabilities (bleeding temperature between 260 and 365°C), finding variations in the selectivity and analytes elution orders depending on the IL structures. Their solvation characteristics were evaluated using the Abraham solvation parameter model, establishing clear correlations between their cation structure and retention capability with respect to certain analytes. The study of relationships between the ILs structure and solvation parameters gives us an idea of the IL stationary phase to be used for specific separations.

Ionic Liquids in Analytical Chemistry: Fundamentals, Advances, and Perspectives

“…One way to increase the liquid range and thermal stability of ILs is by exploiting polycationic ILs . González-Álvarez and co-workers reported the synthesis of seven hexacationic imidazolium-based ILs, most of which exhibited thermal stabilities ranging from 260 to 365 °C. The thermal stability of these polycationic ILs was superior to analogous monocationic ILs and commercially available PEG-based stationary phases. , In addition, these hexacationic ILs possess similar thermal stabilities compared to other families of dicationic and tricationic ILs. , As a result, these stationary phases may be an interesting alternative for the characterization of complex samples such as those currently found in aroma and fragrance, metabolomics, lipidomics, and petrochemical derivatives.…”

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography

“…Over the past decade, research and applications of IL have expanded tremendously because of their properties, such as low melting point, good solubility of organic compounds, low volatility, good stability, and the highly charged nature . Owing to the increasing interest in the field of chromatography, the reports of IL increased sharply during the past few years . IL have been applied in separation science as mobile phase additives or stationary phases in LC , GC , and electrophoresis .…”

Development and evaluation of gas and liquid chromatographic methods for the analysis of fatty amines

“…They also can work up to a maximum temperature of 400°C, depending on the nature of the IL, with very low bleed profiles with MS detection . The IL column selectivity is also different from the classical polar columns .…”