▎ 摘　　要

Herein, we describe a new method for the detection of hydrogen peroxide (H2O2) in food by using an electrochemical biosensor. Initially, ultrafine gold nanoparticles dispersed on graphene oxide (AuNP-GO) were synthesized by the redox reaction between AuCl4- and GO, and thionine-catalase conjugates were then assembled onto the AuNP-GO surface on a glassy carbon electrode. With the aid of the AuNP-GO, the as-prepared biosensor exhibited good electrocatalytic efficiency toward the reduction of H2O2 in pH 5.8 acetic acid buffer. Under optimal conditions, the dynamic responses of the biosensor toward H2O2 were achieved in the range from 0.1 mu M to 2.3 mM, and the. detection limit (LOD) was 0.01 mu M at 3s(B). The Michaelis-Menten constant was measured to be 0.98 mM. In addition, the repeatability, reproducibility, selectivity and stability of the biosensor were investigated and evaluated in detail. Finally, the method was applied for sensing H2O2 in spiked or naturally contaminated samples including sterilized milk, apple juices, watermelon juice, coconut milk, and mango juice, receiving good correspondence with the results from the permanganate titration method. The disposable biosensor could offer a great potential for rapid, cost-effective and on-field analysis of H2O2 in foodstuff.