Four polymeric ionic liquids based on two different cations, poly(1-vinyl-3-hexylimidazolium) and poly(1-vinyl-3-hexadecylimidazolium), combined with two different anions, bis[(trifluoromethyl)sulfonyl]imide (NTf 2-) and chloride (Cl(-)), were combined in various weight percentages and used as sorbent coatings for solid-phase microextraction gas chromatography (SPME-GC). The selectivity of the fiber coatings for 12 test analytes was examined. The extraction efficiency of n-alcohols increased with an increase in the weight percentage of chloride ion in the sorbent coating. The ability to tune the interactions between the coating material and the analytes was exploited and resulted in distinct changes in the limits of detection for hydrogen-bonding analytes with varying chloride ion content in the sorbent coating.
The application of ionic liquids (ILs) as nonderivatizing solvents for the pretreatment and regeneration of cellulose is a growing area of research. Here we report the development of a rapid and simple method for the determination of residual ethanol content in two hydrophilic ILs, 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate. The method utilizes headspace solid-phase microextraction coupled with gas chromatography at elevated extraction temperatures, resulting in rapid equilibration times. The effect of IL water content on the ethanol extraction efficiency is presented. Recovery experiments carried out in real samples gave recoveries ranging from 96.8 to 98.2%.
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