Polymeric Ionic Liquids as CO₂ Selective Sorbent Coatings for Solid-Phase Microextraction

Abstract

Two polymeric ionic liquids (PIL) were synthesized and employed as sorbent coatings in solid-phase microextraction (SPME) for the selective extraction of CO(2). The two coatings, poly(1-vinyl-3-hexylimidazolium) bis[(trifluoromethyl)sulfonyl]imide [poly(VHIM-NTf(2))] and poly(1-vinyl-3-hexylimidazolium) taurate [poly(VHIM-taurate)], exhibited varied selectivity toward CO(2) due to functional groups within in the PIL that imparted different mechanisms of CO(2) capture. Extraction efficiencies were compared to those of two commercial SPME fibers [poly(dimethylsiloxane) (PDMS) and Carboxen-PDMS]. The poly(VHIM-NTf(2)) PIL fiber exhibited comparable extraction efficiency at high CO(2) pressure compared to the Carboxen-PDMS fiber, even though the PIL-based fibers possessed much smaller film thicknesses. Calibration curves generated in pure CO(2) showed that the sensitivity of the poly(VHIM-NTf(2)) coating was comparable to that of the Carboxen-PDMS fiber with both PIL-based fibers exhibiting larger linear ranges and higher extraction-to-extraction reproducibility. The storage ability for selected fibers was examined and revealed that the PIL-based coatings exhibited superior capability in retaining the CO(2) sorbate on the fiber under different storage conditions, particularly for the poly(VHIM-taurate) PIL which reversibly captures CO(2) as a carbamate salt.

Development of a solid-phase microextraction fiber by chemical binding of polymeric ionic liquid on a silica coated stainless steel wire

“…Many researches have illustrated that ILs are promising solvents in sample preparation including liquid-liquid extraction (LLE) [18,19], liquid phase microextraction (LPME) [20][21][22], and solid phase microextraction (SPME) [23][24][25][26]. Liu et al [23] for the first time reported headspace SPME with IL-coated fiber.…”

Development of Novel Solid-Phase Microextraction Fibers

“…Anderson and colleagues for the first time used PILs in SPME coatings [57]. In the pioneer works, PILs were firstly prepared in solutions, and then, the dipping method was used for coating sealed fused-silica capillaries with the PILs [57][58][59][60][61][62][63]. Later, on-fiber polymerization initiated by ultraviolet was also utilized for the preparation of a PIL coating [64].…”

Advances in analytical chemistry using the unique properties of ionic liquids

“…To overcome those drawbacks, Anderson and coworkers designed a series of polymeric ILs (PILs) for use as coatings of SPME [29][30][31]. These PIL-based coatings showed long-term stability and high extraction-toextraction reproducibility, and were successfully used for selective extraction of hydrocarbons and fatty acid methyl esters with high boiling points and low vapor pressures.…”