title: Analysis of beer volatiles by polymeric imidazolium-solid phase microextraction coatings: Synthesis and characterization of polymeric imidazolium ionic liquids.
abstract: Two polymeric ionic liquids, 3-(but-3″-en-1″-yl)-1-[2'-hydroxycyclohexyl]-1H-imidazol-3-ium bis(trifluoromethanesulfonyl)imide (IL-1) and 1-(2'-hydroxycyclohexyl)-3-(4″-vinylbenzyl)-1H-imidazol-3-ium bis(trifluoromethylsulfonyl)imide (IL-2), have been synthesized by a free radical polymerization reaction and used as coatings for solid-phase microextraction (SPME). These new fibers exhibit good film stability, high thermal stability (270-290°C) and long lifetimes, and are used for the extraction of volatile compounds in lemon beer using gas chromatography separation and flame ionization detection. The scanning electron micrographs of the fiber surface revealed a polymeric ionic liquid (PIL) film, which is distributed homogeneously on the fiber. The developed PIL fiber showed good linearity between 50 and 2000μg/L with regression coefficients in the range of 0.996-0.999. The relative standard deviations (RSD) obtained in the peak area were found to vary between 1% and 12%, which assured that adequate repeatability was achieved. The spiked recoveries for three beer samples ranged from 78.4% to 123.6%. Experimental design has been employed in the optimization of extraction factors and robustness assessment. The polymeric IL-1 butenyl fiber showed a greater efficiency compared to the PDMS-DVB (65μm) and CAR-PDMS (75μm) for the extraction of all of the analytes studied.
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: González-Álvarez
authors.forename: Domingo
authors.initials: D
authors.lastname: Blanco-Gomis
authors.forename: Pilar
authors.initials: P
authors.lastname: Arias-Abrodo
authors.forename: Jairo
authors.initials: J
authors.lastname: Pello-Palma
authors.forename: Nicolás
authors.initials: N
authors.lastname: Ríos-Lombardía
authors.forename: Eduardo
authors.initials: E
authors.lastname: Busto
authors.forename: Vicente
authors.initials: V
authors.lastname: Gotor-Fernández
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Gutiérrez-Álvarez
mesh_terms: D001515:Beer / Q000032:analysis*; D002849:Chromatography, Gas; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids; D011108:Polymers / Q000737:chemistry*; D052617:Solid Phase Microextraction / Q000379:methods*; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; D011108:Polymers; D055549:Volatile Organic Compounds
keywords: Experimental design; Gas chromatography; Polymeric ionic liquids; Solid phase microextraction