Analysis of Perfluorinated Compounds in Environmental Water Using Decyl-perfluorinated Magnetic Mesoporous Microspheres as Magnetic Solid-Phase Extraction Materials and Microwave-Assisted Derivatization Followed by Gas Chromatography-mass Spectrometry

Fluorine-functionalized magnetic amino microporous organic network for enrichment of perfluoroalkyl substances

Perfluoroalkyl substances (PFAS) are persistent organic pollutants that pose significant risks to human health and the environment. Efficient and selective enrichment of these compounds was crucial for their accurate detection and quantification in complex matrices. Herein, we report a novel magnetic solid-phase extraction (MSPE) method using fluorine-functionalized magnetic amino-microporous organic network (Fe3O4@MONNH2@F7) adsorbent for the efficient enrichment of PFAS from aqueous samples. The core-shell Fe3O4@MONNH2@F7 nanosphere was synthesized, featuring magnetic Fe3O4 nanoparticles as the core and a porous amino-functionalized MONs coating as the shell, which was further modified by fluorination. The synthesized adsorbent material exhibited high specific surface area, hydrophobicity, and abundant fluorine groups, facilitating efficient and selective adsorption of PFAS via electrostatic attraction, hydrophobic-hydrophobic interactions, fluorine-fluorine interactions, π-CF interactions and hydrogen bonding. Furthermore, the MSPE method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) allowed for the rapid, sensitive, and accurate determination of ultra-trace PFAS in real water samples, human serum, and human follicular fluid. Under optimal conditions, the established MSPE method demonstrated a linear range (2 to 2000 ng L-1), with a correlation coefficient exceeding 0.9977, low limits of detection ranging from 0.54 to 1.47 ng L-1, with a relative standard deviation (RSD) < 9.1%. Additionally, the method showed excellent performance in complex real samples (recovery ratio of 81.7 to 121.6 %). The adsorption mechanism was investigated through kinetic, isotherm, and molecular simulation studies, revealing that the introduction of fluorine groups enhanced the hydrophobic interaction and fluorine-fluorine attraction between the adsorbent and PFAS. This work provides a proof-of-concept strategy for designing adsorbent materials with high efficiency and selectivity by post-modification, which has great potential for the detection and analysis of PFAS in complex samples.

Ionic covalent organic frameworks for the magnetic solid-phase extraction of perfluorinated compounds in environmental water samples

A novel magnetic ionic covalent organic framework (Fe₃O₄@EB-iCOFs) was designed and synthesized. It was then characterized by X-ray diffraction, N₂ adsorption-desorption analysis, and magnetic measurements, among others. The material shows the advantages of ionic property, large surface area, and magnetic responsiveness. It has potential of magnetic solid-phase extraction (MSPE) of perfluorinated compounds (PFCs). A method for the determination of PFCs based on MSPE-HPLC-MS/MS was established. The method has excellent linearity (r ≥ 0.995) in the working range 1-1000 ng L^-1 , good repeatability (1.4-5.8%, n = 6), low limits of detection in the range 0.1-0.8 ng L^-1 and satisfactory recoveries (between 73.9 and 108.3%).