Magnetic graphene oxide-based covalent organic frameworks as novel adsorbent for extraction and separation of...

A novel magnetic graphene oxide-based covalent organic frameworks, was prepared initially by grafting two monomers, tris(4-aminophenyl)amine and 2, 4, 6-triformylphloroglucinol onto Fe₃O₄ nanoparticles attached to graphene oxide scaffolds. It exhibited a regular core-shell spherical structure, super paramagnetism, and desirable adsorbability for five triazine herbicides, and was thus served as adsorbent of magnetic solid-phase extraction. An analytical strategy coupled magnetic solid phase extraction with UHPLC-MS/MS was then developed for the determination of triazine herbicide residues in fruit and vegetable samples. The validation results revealed good linearity in the concentration range of 0.01-200 μg L^-1(r_≥0.9925). LODs of the method were in the range of 0.01-0.05 μg kg^-1, LOQs in the range of 0.05-0.2 μg kg^-1 and recoveries ranged from 72.3 to 112.8%. The results showed that the prepared adsorbent provided desirable adsorption capacity of triazine herbicides, demonstrating great potential in the detection of trace triazine herbicides in complex food matrices.