Nanocomposite of MgFe2O4 and Mn3O4 as Polyphenol Oxidase Mimic for Sensing of Polyphenols

Abstract

Polyphenol oxidase (PPO) mimics have advantage of detection and remediation of poly-phenols. This work demonstrates rapid and sensitive colorimetric detection of phenolic compounds using nanocomposite of magnesium ferrite (MgFe2O4) and manganese oxide (Mn3O4) nanoparticles as PPO mimic. The catalytic properties of MgFe2O4 and Mn3O4 displayed synergistic effect in the nanocomposite. The synthesized nanocomposite and nanoparticles were fully characterized using various analytical techniques. The ratio of MgFe2O4 and Mn3O4 in the nanocomposite was optimized. Catechol and resorcinol were taken as model polyphenols. The best PPO‐activity was shown by MgFe2O4@Mn3O4 nanocomposite with of w/w ratio 1:2. The results correlated with its higher surface area. Reaction parameters viz. pH, temperature, contact time, substrate concentration, and nanopar-ticles dose were studied. The synthesized MgFe2O4@Mn3O4 nanocomposite was used for the detection of catechol in the linear range of 0.1–0.8 mM with the detection limit of 0.20 mM, and resorcinol in the range of 0.01–0.08 mM with the detection limit of 0.03 mM. The estimated total phenolic content of green and black tea correlated well with the conventional method. These results authenticate promising future potential of MgFe2O4@Mn3O4 nanocomposite as PPO‐mimic.