Chemical immobilization of crosslinked polymeric ionic liquids on nitinol wires produces highly robust sorbent coatings for solid-phase microextraction

• Published in: Analytica chimica acta 2014-09, Vol.843, p.18-26
• Main Authors: Ho, Tien D., Toledo, Bruna R., Hantao, Leandro W., Anderson, Jared L.
• Format: Article
• Language: English
• Subjects: Coffee; Crosslinking; Gas chromatography/mass spectrometry; Intermetallics; Ionic liquids; Nickel base alloys; Nickel compounds; Nickel titanides; Nitinol; Polymeric ionic liquids; Shape memory alloys; Solid-phase microextraction; Titanium compounds; Wire
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2014.07.034

[Display omitted] •Crosslinked PIL-based SPME coatings were chemically bonded to nitinol supports.•The SPME fibers exhibited good extraction performance under harsh matrix conditions.•Good recovery of PAEs in hot coffee by direct immersion SPME were obtained.•The SPME fibers are versatile, robust, and possess potential for future applications. Super elastic nitinol (NiTi) wires were exploited as highly robust supports for three distinct crosslinked polymeric ionic liquid (PIL)-based coatings in solid-phase microextraction (SPME). The oxidation of NiTi wires in a boiling (30%w/w) H2O2 solution and subsequent derivatization in vinyltrimethoxysilane (VTMS) allowed for vinyl moieties to be appended to the surface of the support. UV-initiated on-fiber copolymerization of the vinyl-substituted NiTi support with monocationic ionic liquid (IL) monomers and dicationic IL crosslinkers produced a crosslinked PIL-based network that was covalently attached to the NiTi wire. This alteration alleviated receding of the coating from the support, which was observed for an analogous crosslinked PIL applied on unmodified NiTi wires. A series of demanding extraction conditions, including extreme pH, pre-exposure to pure organic solvents, and high temperatures, were applied to investigate the versatility and robustness of the fibers. Acceptable precision of the model analytes was obtained for all fibers under these conditions. Method validation by examining the relative recovery of a homologous group of phthalate esters (PAEs) was performed in drip-brewed coffee (maintained at 60°C) by direct immersion SPME. Acceptable recoveries were obtained for most PAEs in the part-per-billion level, even in this exceedingly harsh and complex matrix.