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Ultraviolet Photoinitiated On-Fiber Copolymerization of Ionic Liquid Sorbent Coatings for Headspace and Direct Immersion Solid-Phase Microextraction
Analytical Chemistry (2012)
  • Tien D. Ho, University of Toledo
  • Honglian Yu, University of Toledo
  • William T.S. Cole, University of Toledo
  • Jared L. Anderson, University of Toledo

A high-throughput method for the production of solid-phase microextraction (SPME) sorbent coatings via ultraviolet (UV) photoinitiated copolymerization of ionic liquid (IL) monomers on a fused silica support is described. The copolymerization of monocationic and dicationic IL cross-linkers was performed “on-fiber” using UV initiated free radical polymerization. Mixtures composed of various amounts of the IL cross-linker, UV initiator (DAROCUR 1173), and IL monomer were dip-coated onto an etched and derivatized fused silica support and placed in a high-capacity UV reactor. The method requires no organic dispersive solvent and is much more rapid compared to traditional methods in which polymeric ionic liquid (PIL) sorbent coatings are prepared by 2,2′-azobis(2-methylpropionitrile) (AIBN)-initiated polymerization. Two ionic liquid-based cross-linkers, namely, 1,8-di (3-vinylimidazolium) octane dibromide ([(VIM)2C8] 2[Br]) and 1,12-di (3-vinylimidazolium) dodecane dibromide ([(VIM)2C12] 2[Br]), were copolymerized with an ionic liquid monomer, 1-vinyl-3-hexylimidazolium chloride ([VHIM][Cl]), to produce polar cross-linked PIL-based SPME sorbent coatings. The cross-linking and immobilization of these coatings make them particularly applicable in direct immersion SPME. The coatings were applied in the extraction of polar analytes, including alcohols, aldehydes, and esters, from aqueous solutions using headspace and direct immersion SPME gas chromatography mass spectrometry (GC/MS). Compared to linear PIL-based sorbent coatings containing the same anions, the cross-linked PIL-based coatings exhibited higher thermal stability and lower bleed, making them ideal for GC/MS. Recovery experiments were performed in deionized, well, and river water. The structural integrity of the sorbent coatings, as well as their analytical precision, was not diminished after 90 extractions from complex samples using headspace and direct immersion SPME.

  • complex samples,
  • cross-linkers,
  • Direct immersion solid-phase microextraction,
  • Dodecane,
  • Gas chromatography-mass spectrometry,
  • headspaces,
  • ionic liquid monomers,
  • polar analytes,
  • river water,
  • silica supports,
  • Solid-phase microextraction,
  • aldehydes,
  • chemical analysis,
  • chlorine compounds,
  • Copolymerization,
  • deionized water,
  • gas chromatography,
  • sorbents
Publication Date
September 19, 2012
Publisher Statement
Reprinted (adapted) with permission from Analytical Chemistry 84 (2012): 9520, doi: 10.1021/ac302316c. Copyright 2012 American Chemical Society.
Citation Information
Tien D. Ho, Honglian Yu, William T.S. Cole and Jared L. Anderson. "Ultraviolet Photoinitiated On-Fiber Copolymerization of Ionic Liquid Sorbent Coatings for Headspace and Direct Immersion Solid-Phase Microextraction" Analytical Chemistry Vol. 84 Iss. 21 (2012)
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