Task-specific Solid-phase Microextraction Using Polymeric Ionic Liquid Sorbent Coatings
Ionic liquids (ILs) are a class of organic molten salts that have melting points lower than 100 °C. One of the distinct properties possessed by some classes of ILs is their high CO2 solubility. The CO2 solubility in ILs lies primarily with the combination of cations and counter anions. By switching the appropriate functionality of the cation and anion, the IL can be manipulated resulting in an increase in the solubility of CO2.
In this study, two different types of polymeric ionic liquids (PILs) were designed, synthesized, and applied as task-specific absorbent coatings for the sequestration of CO2 using solid-phase microextraction (SPME). The poly(1-hexyl-3-vinylimidazolium) cations were paired with two different counter anions, namely taurinate and bis[(trifluoromethyl)sulfonyl]imide (NTf2).
From preliminary work, taurinate is believed to undergo gelation due to a complexation reaction with CO2, while the proposed mechanism for the NTf2-based PIL is physical absorption. Scanning electron microscopy (SEM) was employed to qualitatively prove these hypotheses. Further studies were performed to prove that the morphology changes the PIL coatings under are due to the selective capture CO2, rather than other gases. The solubility of CH4 and N2 were studied and compared with that of CO2. The extraction efficiency of the PIL coated fibers was examined using SPME coupled with gas chromatography (GC).
It is shown that PIL-based coatings possess higher extraction efficiencies compared to commercial SPME fiber coatings with comparable film thicknesses.
Qichao Zhao and Jared L. Anderson
This poster was presented at Pittcon 2011, 13 - 18 March in Atlanta, GA, USA.
Department of Chemistry
The University of Toledo
Toledo, OH, USA