Exploiting the versatility of ionic liquids in separation science
Professor Jared Anderson
Department of Chemistry
University of Toledo
Abstract: An increasing demand on analytical laboratories world-wide seeks to combine sampling and sample preparation methods into a single step. These methods must allow for high throughput analysis of analytes in a variety of matrices while also producing low detection limits, high selectivity, and high enrichment factors. Ionic Liquids (ILs) are an attractive class of non-molecular solvents whose versatility allows them to be incorporated into various microextraction methods. ILs have negligible vapor pressures at room temperature, possess a wide range of viscosities, can be custom-synthesized to be miscible or immiscible with water and organic solvents, often have high thermal stability, and are capable of undergoing multiple solvation interactions with many types of molecules. In addition, ILs can be structurally tuned to modulate desired physio-chemical properties while retaining their unique solvation capabilities. In this talk, the use of ILs and polymeric ionic liquids (PILs) will be described for improving the selectivity, sensitivity, and reproducibility of various microextraction methods including solid-phase microextraction (SPME), single drop microextraction (SDME), and dispersive liquid-liquid microextraction (DLLME). SPME coupled with gas chromatography (GC) was used to evaluate the performance of two different task-specific polymeric ionic liquids, namely poly(1-hexyl-3-vinylimidazolium) taurate and poly(1-hexyl-3-vinylimidazolium) bis[(trifluoromethyl)sulfonyl]imide (NTf2-), for the capture and determination of CO2. It was found that the PIL-based SPME coatings provided significantly higher extraction efficiency of CO2 compared to commercial SPME fiber coatings with similar film thickness. Various functionalized FAP-based ILs employing phosphonium, imidazolium, and pyrrolidinium cations were compared and utilized as extraction solvents in SDME to selectively extract nine polycyclic aromatic hydrocarbons (PAHs) and four small aromatic compounds from environmental water samples. Finally, a DLLME approach using an in-situ metathesis reaction that forms a water-immiscible IL extraction phase is used for the preconcentration of PAHs from environmental water samples. Newer ILs based on functionalized glucaminium-based cations have been synthesized for the selective extraction of boron species from aqueous solutions. The tuneability of the ILs and PILs allows the microextraction technique to be easily coupled with gas chromatography and high performance liquid chromatography given the specific properties of the analyte being determined.
Note: refreshments provided; all welcome.
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Waterloo, ON N2L 3G1