Polymer-Coated Iron Oxide Nanoparticles as an Effective Tool for Histamine Extraction: Synthesis, Characterization, and Application

Histamine accumulation in food products poses significant health risks, necessitating efficient removal strategies to ensure food safety and quality. This study presents the synthesis, characterization, and optimization of poly-(acrylic acid-<i>co</i>-methacrylic acid)-coated iron oxide nanoparticles [ION@P-(AA-<i>co</i>-MAA)] as adsorbents for histamine extraction from food-mimicking buffers. Using a combined Plackett-Burman and central composite design approach, we identified the monomer-to-iron oxide nanoparticle (IONP) ratio and polymerization temperature as critical synthesis parameters significantly influencing nanoparticle size (hydrodynamic diameter ranging from 182 to 801 nm), surface charge (ζ potential from -39.1 to -23.8 mV), polymer coating thickness (weight loss between 3.3% and 5.9%), and histamine adsorption capacity (77.3 to 130.5 mg/g under optimized conditions). The optimized ION@P-(AA-<i>co</i>-MAA) particles demonstrated high adsorption capacities, up to 55 mg/g in soy sauce-mimicking buffer, with efficient magnetic separation facilitated by their superparamagnetic properties. Adsorption isotherm analysis revealed heterogeneous binding sites consistent with polymer coating characteristics, while reusability tests confirmed practical potential in salt-rich environments. This work advances the development of functionalized magnetic nanoparticles for histamine removal, offering a scalable, reusable platform to enhance food safety and support low-histamine food production.