Rapidly covalent immobilization of β-ketoenamine-linked covalent organic framework on fibers for efficient solid-phase microextraction of phthalic acid esters

Rapid and convenient preparation of covalent organic framework (COF) coated fibers is of great significance to solid-phase microextraction (SPME) technology. In this work, a novel chemical preparation strategy was established for rapid fabrication of β-ketoenamine-linked COF coatings, in which clay-like starting materials of COFs were first wrapped on the fiber surface through self-viscosity and further fixed on the fiber in an oven via chemical bonding. Based on this strategy, four different COF (TpTph, TpPa-1, TpBD and TpTpb) coated fibers was fabricated within 1 h, which is very rapid compared to the recently reported research. Moreover, the strategy also demonstrates the good general applicability for COF fiber preparation. Subsequently, the TpTph coated fiber was used to develop a new SPME method for gas chromatography-tandem mass spectrometry (GC-MS/MS) of trace phthalic acid esters (PAEs) in environmental water. The developed analytical method compared to the previous SPME methods for PAEs based on other sorbents possesses low limits of detection (LODs, 0.02-0.08 ng L-1), and better or comparable precision (RSD ≤9.4%, n = 6), and relatively short extraction time. Furthermore, the trace PAEs (0.27-11.62 ng L-1) in the real water samples were successfully detected with recoveries of 82.2-117.5%. The above results indicates that the proposed fiber preparation strategy is reliable and opens a potential avenue for rapid and facile fabrication of COF coated fibers.