Magnetic graphene oxide−based covalent organic frameworks as novel adsorbent for extraction and separation of triazine herbicides from fruit and vegetable samples

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 Fe 3 O 4 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.