Magnetic Covalent Organic Framework for the Simultaneous Extraction of Eight Sulfonamide Antibiotics in Fish and...

As a kind of adsorption material with excellent properties, covalent organic frameworks (COFs) have a broad application prospect in the field of sample pretreatment. Herein, a magnetic COF was constructed by combining magnetic nanospheres with a stable azine-bonded COF via the monomer-mediated in-situ growth strategy for the enrichment and determination of sulfonamide antibiotics. The magnetic COF has good magnetic properties, an appropriate specific surface area, and high stability, and is an excellent adsorbent for magnetic solid-phase extraction. The adsorption mechanism study showed that the large conjugated system and the rich N element of the azine-bonded COF provided abundant π-π interactions and hydrogen-bonding sites, which were beneficial to its interaction with sulfonamide antibiotics. An analytical method for the detection of eight sulfonamides in fish and chicken was developed by combining magnetic extraction with capillary electrophoresis analysis. Under the optimal conditions, the proposed method showed good linearity between the peak areas and the concentrations of eight sulfonamides from 0.1 to 5.0 µg/mL, with correlation coefficients greater than 0.98 and limits of detection from 0.008 to 0.057 µg/mL. This work provides an alternative method to capture and detect sulfonamide antibiotics that is highly efficient, rapid, and sensitive.