A green method for the determination of PFAS in environmental water matrices: Dispersive solid phase extraction using MOF NH2-UiO-66 and high-resolution mass spectrometry analysis

Abstract

A rapid and efficient method was developed for the extraction of nine per- and polyfluoroalkyl substances (PFAS) from environmental water samples. The method utilizes a metal-organic framework (MOF)-assisted dispersive solid-phase extraction (d-SPE) approach, employing the amino-functionalized Zr(IV) MOF NH2-UiO-66. Analytical determination was performed using liquid chromatography coupled with tandem high-resolution mass spectrometry (LCHRMS).

Key parameters influencing the extraction efficiency, including extraction time, elution time, and sample volume, were systematically optimized. Based on the results, the optimal conditions were determined to be 15 min of extraction, 5 min of elution, and a sample volume of 10 mL. The method's accuracy, repeatability, and linearity were thoroughly validated, demonstrating robust performance. Recoveries exceeded 70 % with relative standard deviations (RSDs) below 20 %, and the method achieved detection limits ranging from 4 to 95 ng L⁻¹. Additionally, the reusability of the MOF material was evaluated, showing that it could be reused up to three times without significant loss in efficiency.

Before application to real samples, the "green" attributes of the newly developed MOF-based dSPE-LCHRMS method were assessed using the ComplexMoGAPI index. The evaluation yielded a total score exceeding 75, categorizing the method as eco-friendly. The method's efficacy was further validated using various environmental water matrices with different levels of complexity, including runoff water, river water, seawater, and wastewater effluent.