Synthesis of MOF@COF Hybrid Magnetic Adsorbent for Microextraction of Sulfonamides in Food and Environmental Samples

Covalent organic framework (COF) was decorated on the surface of magnetic metal organic framework (MOF) to yield novel MOF@COF hybrid magnetic nanospheres, which were employed as a magnetic adsorbent for extraction of sulfonamides (SAs) in food and environmental samples. The morphology and structure of the synthesized hybrid nanospheres were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, and nitrogen physisorption. Conditions for magnetic solid phase extraction for SAs were optimized by using the MOF@COF hybrid magnetic adsorbent. By coupling with high-performance liquid chromatography, a facile and sensitive method was developed for the determination of six SAs, showing good linearity in the range of 10–2000 ng/mL with R 2  > 0.99, high sensitivity with LODs of 0.1–0.5 ng/mL, and high reproducibility with RSDs < 3.9%. The established method was also applied to the rapid and efficient extraction of SAs in real samples such as tap water, pork, chicken, and shrimp samples.