A core-shell structured magnetic covalent organic framework as a magnetic solid-phase extraction adsorbent for phenylurea herbicides

In this work, a core-shell structured magnetic covalent organic framework named as M-TpDAB was constructed with 3,-diaminobenzidine (DAB) and 1,3,5-triformylphloroglucinol (Tp) as building units. MTpDAB was characterized by infrared spectroscopy, nitrogen adsorption-desorption isotherms, powder Xray diffraction, scanning electron microscopy and transmission electron microscopy. Using the M-TpDAB as adsorbent, a simple and highly effective method was proposed for preconcentrating phenylurea herbicides before high performance liquid-phase chromatography analysis. In the optimized conditions, a good linearity was achieved within the range of 0.15-100 ng mL & minus;1 for water sample, 1.0-100.0 ng mL & minus;1 for tea drink samples. The limits of detection for the analytes were 0.05-0.15 ng mL & minus;1 for water sample and 0.30-0.50 ng mL & minus;1 for drink samples. Satisfactory recoveries of spiked target compounds were in the range of 84.6%-105% for water sample and 80.3%-102% for tea drink samples. Finally, the M-TpDAB based method was successfully used to determine phenylurea herbicides in tea drinks and water samples, demonstrating a good alternative for analyzing trace level of phenylurea herbicides in water samples. (c) 2021 Elsevier B.V. All rights reserved. <comment>Superscript/Subscript Available</comment