Chemical Engineering Journal, Vol.356, 926-933, 2019
beta-Ketoenamine-linked covalent organic framework coating for ultra-high-performance solid-phase microextraction of polybrominated diphenyl ethers from environmental samples
Covalent organic frameworks (COFs) via Schiff base-type linkages (1,3,5-triformylphloroglucinol-par-aphenylenediamine, TpPa-1), as an ideal coating, possesses significant potential for solid-phase microextraction (SPME) due to their fascinating properties, such as outstanding thermal and chemical stabilities, inherent porosity, and high crystallinity. A novel SPME device was fabricated based on TpPa-1 as an enrichment coating for capturing trace polybrominated diphenyl ethers (PBDEs). This TpPa-1 coating exhibited a superior enrichment capacity in "catching" PBDEs over commercial SPME fibers. Such performance is attributed to multiple factors, including the coating's hydrophobic nature, p-p stacked architectures, large specific surface area, high thermal stability, and size-matching effect. High enhancement factors of 2035-6859, low detection limits of 0.0058-0.022 ng L-1, satisfactory linear range of 0.01-100 ng L-1, good repeatability of 4.86%-9.33%, and excellent reproducibility of 5.62%-9.85% were achieved. Finally, as expected, as the most sensitive SMPE technique for detecting PBDEs, to the best of our knowledge, the developed SPME procedure in combination with gas chromatography-negative chemical ion-mass spectrometry analysis was proven to be ultrasensitive, dependable, and practical in analyzing PBDE species in real water. These exceptional results signify that the proposed method offers a fresh prospect to extend the potential applications of COFs to pick up pollutants at ultra-low levels from environmental samples.