Esters 2 Extraction 2 Magnetic solid-phase extractions Magnetism 2 Phase separation 2 Active esters 1 Adsorption 1 Adsorption behavior 1 Adsorption behaviour 1 Alternative method 1 Beverages 1 Brunauer-emmett-teller surface areas 1 Chromatography 1 Fe3O4 magnetic nanoparticles 1 Fourier transform infrared spectroscopy 1 Gas chromatography 1 Gas chromatography-flame ionization detectors 1 Gas generators 1 Graphene 1 Graphene oxide nanocomposites 1 Graphene oxide/polyacrylamide/Fe3O4 1 Graphene oxide/polyacrylamide/fe3O4 1 Graphene oxides 1 High resolution transmission electron microscopy 1 Ionization of gases 1 Liquid-liquid extraction 1 Magnetic nano-particles 1 Magnetic nanoparti cles (MNPs) 1 Magnetic solid phase extraction 1 Magnetic solid-phase extraction 1