Architectural engineering inspired in situ growth of covalent organic frameworks as outstanding fiber coating for solid-phase microextraction of phenols

The development of a straightforward method for preparing high-performing solid-phase microextraction (SPME) coatings is of paramount importance. In this work, inspired by architectural engineering, a simple and rapid synthetic strategy was developed to grow covalent organic frameworks (COFs) in situ on the surface of stainless steel wire as the SPME coating. Subsequently, the COF-coated fiber was applied for the extraction of phenols. Due to the avoidance of using any binder, the porous structure of COFs was well preserved, leading to a superior extraction performance, surpassing physically adhered COF coatings and commercial polyacrylate coatings. Combined with gas chromatography-mass spectrometry, an efficient and sensitive analytical method for the quantification of phenols was established with high enhancement factors (11080–58762), wide linear ranges (2–10000 ng·L−1), low limits of detection (0.39–0.72 ng·L−1), and good repeatability (RSD, ≤7.9%). Moreover, the feasibility of the established method was demonstrated by the determination of target phenols in certified reference materials (water and soil) with satisfactory results. The proposed in situ preparation method provides a easy and efficient approach to prepare high-performance COF-coated fiber for the efficient SPME of trace phenols from complex matrices in practical samples.