Facil and green synthesis of biocompatible nanocomposites based on iron oxide/reduced graphene oxide for determination of Vanillin in Food Samples: Response surface methodology optimization

Additives analysis plays important role in food quality control and has a great impact on public health. Therefore, rapid detection of these compounds in food samples is important in food safety. In this study, reduced graphene oxide /Fe3O4 nanocomposite (rG-Fe3O4-NC) was synthesized in the presence of sour lemon peel extract as a reducer and stabilizer agent in aqueous solution. For the first time multivariate optimization based on rotatable central composite design (RCCD) coupled with response surface methodology (RSM) was used to optimize effective experimental variables for fabrication of electrode. An experimental design has been used to examine and optimize the impacts of diverse experimental parameters like the pH and concentration of the nanocomposite in rG-Fe3O4-NC. The optimal conditions were pH: 6 and the concentration of the nanocomposite: 8%. The synthesized nanocomposites were characterized by TEM and XRD techniques. The rGO modified carbon paste electrode (rG-Fe3O4-NC/CPE) was used as a highly sensitive electrochemical sensor for the detection of vanillin. Interference of vitamin B2, methionine, valine, glycine and KBR, KCl and glucose were checked in the presence of 25 µM vanillin at surface of rG-Fe3O4-NC/CPE with acceptable error 5%. Results confirmed that 500-folde of above compounds have not any important interference in monitoring process of 25 µM vanillin. The vanillin sensor showed linear range between 01 nM – 250 μM and a low detection limit of 0.3 nM. Finally, the rG-Fe3O4-NC/CPE was successfully used for determining vanillin in food samples. Therefore, this sensor can be used in food industry to the online determination of vanillin in flavored milks and ice cream.