Green synthesis of Pd/Fe3O4 composite based on polyDOPA functionalized reduced graphene oxide for electrochemical detection of nitrite in cured food

A green and effective route was used to synthesize Pd/Fe3O4/polyDOPA/RGO for in situ nucleation and growth of Fe3O4 and Pd on reduced graphene oxide (RGO), based on the polyDOPA (3,4-Dihydroxy-l-phenylalanine, DOPA) coating as a versatile platform. The Pd/Fe3O4/polyDOPA/RGO composite showed superior electrocatalytic activity toward nitrite oxidation due to electronic effect. The amperometric response results demonstrated that Pd/Fe3O4/polyDOPA/RGO modified glassy carbon electrode was further employed to determine nitrite with a wide linear range of 2.5-6470 mM and a low detection limit of 0.5 mM. With good anti-interference toward various anions and cations and good stability, the proposed sensor was successfully applied for the determination of nitrite in Yellow River water and sausage extract with satisfactory results. Moreover, this sensor could be used to effectively monitor the change of nitrite content during the rapid corruption of Chinese cabbage. It was found that the content of nitrite reached at the maximum level within one day and then decreased to a low level after three day-corruption, which was agreed with the tendency measured by ionic chromatography. (C) 2017 Elsevier Ltd. All rights reserved.