PMID- 32920274 OWN - NLM STAT- MEDLINE DCOM- 20201130 LR - 20201130 IS - 1873-7072 (Electronic) IS - 0308-8146 (Linking) VI - 337 DP - 2021 Feb 1 TI - Facile extraction and determination of organophosphorus pesticides in vegetables via magnetic functionalized covalent organic framework nanocomposites. PG - 127974 LID - S0308-8146(20)31836-7 [pii] LID - 10.1016/j.foodchem.2020.127974 [doi] AB - Facile enrichment and determination of trace organophosphorus pesticides (OPPs) in foods has been a constantly pursuing goal in food safety field. Herein, Zr(4+)-immobilized covalent organic frameworks (Fe(3)O(4)@COF@Zr(4+)) have been first constructed and utilized as the powerful adsorbents for magnetic solid-phase extraction (MSPE) of OPPs. Owing to the pi-pi stacking interaction, hydrogen bonding and Zr(4+)-phosphate coordination reaction, the composites exhibited excellent selectivity and superior affinity to OPPs. Under optimized conditions, the proposed MSPE method coupled with GC-FPD showed good linearity (R(2) >/= 0.9990) and yielded low limits of detection (0.7-3.0 mug kg(-1)) for OPPs. Moreover, the developed method was successfully employed for the quantitation of OPPs in spiked vegetable samples and obtained satisfactory recoveries in the range of 87-121% with the relative standard deviations (RSDs)