In this study, it was aimed to produce Fe₃O₄ magnetic nanoparticles from the Euphorbia plant (Euphorbia amygdaloides) using a simple and economical green biosynthesis method as a new method. Iron oxide nanoparticles have a large number of applications (health, drug development, biosensor, imaging systems etc.) One of these Fe₃O₄ magnetic nanoparticles (MNPs) has been found to be used repeatedly in various application areas due to their properties. Fe₃O₄ MNPs were synthesized using euphorbia (Euphorbia amygdaloides) plant extract and Fe^+2/+3 solution. The characterization analysis was performed using UV-Vis spectrophotometer, SEM, XRD and FTIR devices. Then, the mimetic (enzyme-like activity) properties of MNPs were investigated. It was determined that Fe₃O₄ MNPs mimics enzymes. They have similar properties and catalysis power to natural peroxidases. In the targeted new method, glucose oxidase (GOx) enzyme with Fe₃O₄ MNPs which mimic peroxidase have been used for developing a spectrophotometric method for highly sensitive and stable - enzymatic glucose determination in different foods. The method developed was found to be linear in the 0.25-1 g/L glucose range. The optimal operating parameters of the biosensor were found temperature, (45 ^oC), pH (4.0), metal ion concentration (5 mM) and H₂O₂ concentration (12.5 Mm), respectively. In addition, this method has shown a high selectivity to glucose compared to other sugars such as sucrose, lactose, fructose and raffinose.