▎ 摘　　要

NOVELTY - Preparing graphene quantum dot-based petroleum liquid product comprises (i) adding concentrated sulfuric acid and concentrated nitric acid into the petroleum liquid product and ultrasonicating to obtain dispersion-based petroleum liquid product, (ii) subjecting dispersion-based petroleum liquid product to an oxidation reaction, stirring in a reactor, cooling to room temperature and adjusting pH to neutral with alkali to obtain crude product of petroleum liquid base product, and (iii) centrifuging the crude product of petroleum liquid base product obtained in step (ii), collecting the supernatant through a microporous membrane, dialyzing and intercepting to obtain final product. USE - The graphene quantum dot-based petroleum liquid product is useful as fluorescent probe, photoelectric material and photocatalysis material in the field of biological imaging, photodynamic therapy, thermal therapy and ion detection in water body and/or in vivo (claimed). ADVANTAGE - The petroleum liquid product: has simple preparation process, low cost, small size of graphene quantum dot, excellent water solubility and dispersibility. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for graphene quantum dot-based petroleum liquid product obtained by above method.