▎ 摘　　要

NOVELTY - The preparation method of graphene oxide-loaded cobalt tetroxide nanocomposite material involves (i) dissolving graphene oxide and cobalt acetate tetrahydrate in absolute ethanol, stirring, adding ammonia, stirring, (ii) transferring the resulting suspension into a high pressure autoclave, sealing, reacting, (iii) cooling the reaction mixture to room temperature, centrifugally separating the reaction product, washing with ultrapure water for several times, and (iv) drying in a vacuum oven at 60-70 degrees C for 3-5 hours to obtain black powder, and storing the black powder in a dryer. USE - Preparation of graphene oxide-loaded cobalt tetroxide nanocomposite material used in detection of vitamin C in food (claimed). ADVANTAGE - The method enables the preparation of graphene oxide-loaded cobalt tetroxide nanocomposite material having excellent catalytic capacity, and high selectivity, sensitivity, and visualization ability. DETAILED DESCRIPTION - The preparation method of graphene oxide-loaded cobalt tetroxide nanocomposite material involves (i) dissolving graphene oxide and cobalt acetate tetrahydrate in absolute ethanol, stirring, adding 25-28% ammonia, stirring for 8-15 minutes, (ii) transferring the resulting suspension into a high pressure autoclave, sealing, reacting at 140-165 degrees C for 2-4 hours, (iii) cooling the reaction mixture to room temperature, centrifugally separating the reaction product, washing with ultrapure water for several times, until the supernatant is close to neutral, and (iv) drying in a vacuum oven at 60-70 degrees C for 3-5 hours to obtain black powder, and storing the black powder in a dryer. An INDEPENDENT CLAIM is included for application of graphene oxide-loaded cobalt tetroxide nanocomposite material in detection of vitamin C in food by using 3,3',5,5'-tetramethyl benzidine as chromogenic substrate.