Polymeric metal-containing ionic liquid sorbent coating for the determination of amines using headspace solid-phase microextraction

This study describes the design, synthesis, and application of polymeric ionic liquid sorbent coatings featuring nickel metal centers for the determination of volatile and semivolatile amines from water samples using headspace solid-phase microextraction. The examined polymeric ionic liquid (PIL) sorbent coatings were composed of two ionic liquid monomers (tetra(3-vinylimidazolium)nickel bis[(trifluoromethyl)sulfonyl]imide [Ni²⁺ (VIM)₄ ] 2[NTf₂ ^- ] and 1-vinyl-3-hexylimidazolium [HVIM⁺ ][NTf₂ ^- ]), and an ionic liquid cross-linker (1,12-di(3-vinylimidazolium)dodecane [(VIM)₂ C₁₂ ²⁺ ] 2[NTf₂ ^- ]). With these ionic liquid monomers and cross-linkers, three different types of coatings were prepared: PIL 1 based on the neat [Ni²⁺ (VIM)₄ ] 2[NTf₂ ^- ] monomer, PIL 2 consisting of the [Ni²⁺ (VIM)₄ ] 2[NTf₂ ^- ] monomer with addition of cross-linker, and PIL 3 composed of the [HVIM⁺ ][NTf₂ ^- ] monomer and cross-linker. Analytical performance of the prepared sorbent coatings using headspace solid-phase microextraction gas chromatography-mass spectrometry was compared with the polydimethylsiloxane and polyacrylate commercial coatings. The PIL 2 sorbent coating yielded the highest enrichment factors ranging from 5500 to over 160 000 for the target analytes. The developed headspace solid-phase microextraction gas chromatography-mass spectrometry method was applied for the analysis of real samples (the concentration of amines was 200 μg/L), producing relative recovery values in the range of 90.9-120.0% (PIL 1) and 83.0-122.7% (PIL 2) from tap water, and 84.8-112.4% (PIL 1) and 79.2-119.3% (PIL 2) from lake water.