▎ 摘　　要

NOVELTY - Preparing green fluorescent graphene quantum dot comprises dissolving reactive red 2 in water, adding L-cysteine , ultrasonically mixing, placing in a hydrothermal reactor and hydrothermally reacting at 180-240℃for 8-16 hours to obtain green fluorescent graphene quantum dot solution. USE - The quantum dot is useful in the selective detection of metal ions aluminum (III) ion and iron (III) ions in aqueous solutions (claimed). ADVANTAGE - The method is simple and economical. The quantum dot has significant effect as a fluorescent probe for detecting metal ions and can quickly detect metal ions aluminum (III) ion and iron (III) ions in water within 30 seconds.