Confinement effect of ionic liquid: Improve of the extraction performance of parent metal organic framework for phthalates.

In order to better identify the hazards of pollutants, developing the analytical methods that can sensitively detect and precisely monitor the content of trace pollutants has been the constant pursuit. In this paper, a new solid phase microextraction coating-ionic liquid/metal organic framework (IL/MOF) was obtained through the IL-induced strategy and used for the solid phase microextraction (SPME) process. IL was introduced into metal-organic framework (MOF) cage based on the anion of ionic liquid could interact strongly with the zirconium nodes of UiO-66-NH. The introduction of IL not only increased the stability of composite, the hydrophobicity of IL also changed the environment of MOF channel, providing the hydrophobic effect to the targets. The confinement effect of IL effectively improved the extraction performance of parent MOF and the extraction performance of synthesized IL/UiO-66-NH for phthalates (PAEs) were 1.3-3.0 times that of parent UiO-66-NH. Thanks to the strong interaction force (hydrogen bonding interaction, π-π stacking, hydrophobic interaction force), the IL/UiO-66-NH-coated fiber coupled with gas chromatography-mass spectrometer showed a wide linear ranges (1-5000 ng L) with good correlation (R, 0.9855-0.9987), lower detection limit (0.2-0.4 ng L) and satisfactory recoveries (95.3-119.3%) for PAEs. This article is dedicated to provide another way to improve the extraction performance of material.