Rapid fabrication of magnetic covalent organic frameworks for the effective extraction and determination of sulfonamides in shrimp samples

In this work, a magnetic covalent organic frameworks (COFs) named Fe3O4@TpBD was rapidly synthesized by an ultrasonic method, which reduced the synthesis time to 1.5 h. Fe3O4@TpBD was used as a magnetic solid-phase extraction (MSPE) adsorbent for the extraction and enrichment of five common sulfonamides, and there were different enrichment multiples ranging from 5 to 30. The limits of detection (LODs) of this method were 0.31–0.73 ng mL−1, the limits of quantitation were 1.03–2.44 ng mL−1, and the intraday and interday relative standard deviations (RSDs) were