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• A porous magnetic material (Fe 3 O 4 @3DGA@ZIF-8) is synthesized which is easy to recycle. • The isothermal and kinetic curves were fitted to illustrate the adsorption mechanism a certain extent. • Fe 3 O 4 @3DGA@ZIF-8 have a high specific surface area, fast adsorption rate, and fairly repeating utilization factor. • Fe 3 O 4 @3DGA@ZIF-8 is very effective in removing caffeine, especially in adsorbing in tea soup - all over 98%. As more and more adverse health effects of caffeine are being discovered, decaffeinated drinks are receiving increasing attention. In this work, a magnetic imidazole zeolite backbone compounded with three-dimensional graphene was successfully synthesized as a solid adsorbent using a layer-by-layer self-assembly technique, which can rapidly and effectively adsorb caffeine from tea. Meanwhile, the structure and properties of caffeine in tea were investigated by various physicochemical characterization tools. The analytical data showed that Fe 3 O 4 @3DGA@ZIF-8 had a specific surface area of 162.9754 m2/g and an adsorption capacity of up to 19.57 mg/g with a maximum adsorption rate of 96.55%, which could be maintained with good adsorption repeated utilization three times. The adsorption isotherm and the adsorption kinetic better fit with the Langmuir model and the preudo-second order kinetic model, respectively. Therefore, Fe 3 O 4 @3DGA@ZIF-8 is a good magnetic adsorbent for the separation and the effective removal of caffeine from tea sample. [ABSTRACT FROM AUTHOR]

[Display omitted] • One-pot synthesis of ZIF-67@FePc effectively enhances the crystallinity of the material. • Iron and cobalt bimetallic synergies effectively improve GA sensor response. • Co/FeO X @NC-800/GCE has an ultra-sensitive electrochemical response to gallic acid. • Co/FeO X @NC-800/GCE successfully used for GA detection in various food products. Gallic acid is widely used as an antioxidant in food because of its good antioxidant function, but excessive intake induces side effects in humans, so it is essential to devise a highly responsive technique for detecting gallic acid. In this work, we synthesized ZIF-67@FePc by the one-pot method. The synthesized material is more stable at high temperatures compared to ZIF-67 and maintains its original morphology during pyrolysis, when iron was introduced as a second metal active site during the synthesis process. Subsequently, Co/FeO X @NC-800 was employed to fabricate a GA sensor on a GCE. The developed sensor exhibited remarkable sensitivity towards GA, featuring a low LOD of 1.30 nM and a linear range spanning from 5 to 4500 nM. The electrochemical sensors we have prepared also showed good selectivity, stability, and reproducibility. It has been successfully employed for detecting GA in actual samples such as apples, grapes, tomatoes, and red wine. [ABSTRACT FROM AUTHOR]