Development of a polymeric ionic liquid coating for direct-immersion solid-phase microextraction using polyhedral oligomeric silsesquioxane as cross-linker

A novel solid-phase microextraction (SPME) fiber was developed by chemical binding of a crosslinked polymeric ionic liquid (PIL) on the surface of an anodized Ti wire, and was applied in direct-immersion mode for the extraction of perfluorinated compounds (PFCs) from water samples coupled with high performance liquid chromatography–tandem mass spectrometry analysis. The PIL coatings were synthesized by using 1-vinyl-3-hexylimidazolium hexafluorophosphate as monomer and methylacryloyl-substituted polyhedral oligomeric silsesquioxane (POSS) as cross-linker via free radical reaction. The proposed fiber coating exhibited high mechanical stability due to the chemical bonding between the coating and the Ti wire surface. The integration of POSS reagent enhanced the organic solvent resistance of the coating. The parameters affecting the extraction performance of the fiber coating including extraction time, pH of solution, ionic strength and desorption conditions were optimized. The developed PIL-POSS fiber showed good linearity (R < 0.998) between 0.1 and 50 ng mL−1 with method detection limits ranging from 0.005 to 0.08 ng mL−1 depending on the analyte, and with relative standard deviation for single-fiber repeatability and fiber-to-fiber reproducibility less than 8.6% and 9.5%, respectively.