Amidoxime covalent organic framework@Fe₃O₄ based magnetic solid-phase extraction for rapid and sensitive...

The unintentional dissemination of uranium into environment poses substantial risks to both food sources and human populations. An advanced method for convenient and accurate detection of uranium in food is thus a pressing need. Herein, a novel magnetic amidoxime functionalized covalent organic framework (TpDb-AO@Fe₃O₄), prepared with 2,5-dinitrobenzonitrile, 1,3,5-triformylphloroglucinol and hydroxylamine hydrochloride, was synthesized as adsorbent for magnetic-solid phase extraction (MSPE) of UO₂²⁺. Furthermore, a TpDb-AO@Fe₃O₄ based MSPE coupled with UV-vis spectrophotometer was successfully developed to realize the determination of uranyl ions with low limit of detection of 1.63 μg L^-1, wide linear range of 10 - 200 μg L^-1. The spiking recoveries in real seafood samples (tuna, yesso scallop, kelp, eel, hairtail) ranged from 94.1 % - 106.8 %. The intraday (n = 5) and interday (n = 5) relative standard deviation (RSD) for determination of UO₂²⁺were 3.33 % and 6.23 %, respectively. This approach represents an advancement in the rapid extraction and sensitive quantification of trace uranium contaminants in food matrices, thereby contributing to enhanced environmental monitoring and public health safeguards.