Nanocomposite of MgFe(2)O(4) and Mn(3)O(4) as Polyphenol Oxidase Mimic for Sensing of Polyphenols

Polyphenol oxidase (PPO) mimics have advantage of detection and remediation of polyphenols. This work demonstrates rapid and sensitive colorimetric detection of phenolic compounds using nanocomposite of magnesium ferrite (MgFe(2)O(4)) and manganese oxide (Mn(3)O(4)) nanoparticles as PPO mimic. The catalytic properties of MgFe(2)O(4) and Mn(3)O(4) displayed synergistic effect in the nanocomposite. The synthesized nanocomposite and nanoparticles were fully characterized using various analytical techniques. The ratio of MgFe(2)O(4) and Mn(3)O(4) in the nanocomposite was optimized. Catechol and resorcinol were taken as model polyphenols. The best PPO-activity was shown by MgFe(2)O(4)@Mn(3)O(4) 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 nanoparticles dose were studied. The synthesized MgFe(2)O(4)@Mn(3)O(4) 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 MgFe(2)O(4)@Mn(3)O(4) nanocomposite as PPO-mimic