Hydroxyl-functionalized three-dimensional covalent organic framework for selective and rapid extraction of...

The wide utilization of organophosphorus pesticides (OPPs) results in a potential threat to ecosystem and human health. The essential extraction process in practical OPPs analysis always suffers from the low efficiency due to the limited accessible active sites and interactions in the adsorbents. Here, we report a rational design and synthesis of a novel hydroxyl-functionalized three-dimensional covalent organic framework (3D COF-OH) named JNU-6 with ordered porous structure and multiple interactions as the adsorbent for rapid and selective dispersive solid phase extraction (DSPE) of OPPs. The 3D COF-OH based DSPE was coupled with gas chromatography-flame thermionic detection (GC-FTD) for the determination of four selected OPPs with low limits of detection of 0.15-0.39 ng mL^-1, wide linear range of 1-1100 ng mL^-1. The developed method gave good precision (relative standard deviation of 1.6-8.5% (n = 5)) and recoveries of 86-106% for the determination of OPPs in complicated fruit and vegetable samples. This work reveals the high practical potential of functionalized 3D COFs as adsorbents for effective extraction of trace contaminants in complicated samples.