▎ 摘　　要

NOVELTY - An amorphous carbon and oxidizing acid are oxidation-reacted, to obtain graphene quantum dots. The oxidizing acid is nitric acid. The amorphous carbon has mesh particle size of more than 100 mesh. USE - Production of graphene quantum dots used for detection of urea (claimed). ADVANTAGE - The method enables production of graphene quantum dots having excellent sensitivity, by simple method. The urea content is efficiently detected using the graphene quantum dots. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for detection of urea, which involves determining concentration of urea by fluorescence spectrophotometry using solvent and buffer solution, and mixing graphene quantum dots and urease.