Uniform spherical covalent organic framework for efficient extraction of 13 per-and polyfluoroalkyl substances in Chinese medicinal materials

Long-term consumption or exposure to Chinese medicinal materials contaminated with per- and polyfluoroalkyl substances (PFASs) poses a potential risk to human health. Owing to the low contents of PFASs in the complex matrix of Chinese medicinal materials, it is imperative to develop high-performance adsorbents for the enrichment of PFASs prior to analysis. Covalent organic frameworks (COFs) are widely used as adsorbents because of their large surface area and good chemical stability. In this study, C N bonded spherical TPB-DMTP-COF was prepared by a simple Schiff base reaction using acetonitrile as solvent at room temperature. The materials exhibited abundant porous structures, exceptional hydrophobicity, superb thermostability, excellent crystalline structure, and a substantial surface area of 1419 m 2 g −1 and thus could be outstanding adsorbents for solid-phase extraction (SPE) of PFASs. The adsorption experiments showed that the adsorption capacity and adsorption rate of PFASs increased with the extension of alkyl carbon chain of PFASs molecule. In essence, the strong adsorption affinity could be attributed to the hydrophobic characteristics and Van der Waals force. The proposed approach based on SPE and liquid chromatography-tandem mass spectrometry achieved low limits of detection (0.01–0.04 μg kg −1 ), good precision (< 4.7%) and excellent linearity for PFASs ranging from 0.1 to 10 ng mL −1 (R 2  ≥ 0.997). The actual amounts of PFASs varied from 0.08 μg kg −1 to 2.67 μg kg −1 in seven Chinese medicinal materials. The satisfactory recoveries (91.6%–105.8%) and good repeatability (12 times) for simultaneous analysis of 13 PFASs were obtained. This research presents a promising alternative for the sensitive analysis of PFASs at trace levels in complex matrices.