▎ 摘　　要

NOVELTY - A modified electrode comprises substrate electrode, a platinum-gold three-dimensional graphene composite material, myoglobin molecule and nafion film sequentially fixed on the substrate electrode, where the substrate electrode is a carbon ion liquid modified electrode. USE - Modified electrode for preparing electrochemical sensor device, electrocatalytic reduction and detection of trichloroacetic acid and sodium nitrite and use in detection of trichloroacetic acid and sodium nitrite (all claimed). DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for preparing a modified electrode, which involves taking an appropriate amount of platinum-gold-three-dimensional graphene composite dispersed droplets on surface of the carbon ionic liquid electrode and drying to obtain a platinum-gold-three-dimensional graphene composite / carbon ionic liquid electrode, applying appropriate amount of myoglobin solution to surface, drying myoglobin/ platinum-gold-three-dimensional graphene composite / carbon ionic liquid electrode, applying an appropriate amount of Nafion (RTM: Sulfonated tetrafluoroethylene based fluoropolymer-copolymer) ethanol solution to surface of the electrode and drying to obtain the finished product.