▎ 摘　　要

NOVELTY - Preparation of blue-emitting b-graphene quantum dot (GQD)s comprises weighing 2 g citric acid in 50 mL round bottom flask, liquefying at 145 degrees C, heating, absorbing orange liquid, adding 100 mL sodium hydroxide solution, mixing for 15 minutes, neutralizing with nitric acid, refrigerating at 4 degrees C, dialyzing, purifying and vacuum drying. USE - Method of preparing blue-emitting b-graphene quantum dot (claimed). ADVANTAGE - The quantum dot has good water solubility, better chemical inertness, biocompatibility and low toxicity.