▎ 摘　　要

NOVELTY - A nitrogen-copper doped graphene compound (I), is new. USE - The new compound (I) is useful as quantum dots for detecting quercetin and tetracycline antibiotics including doxycycline (all claimed). ADVANTAGE - The compound (I) can be prepared by a simple and economical method, which ensures large detection range and low detection limit. The use of nitrogen doping improves the quantum yield of graphene quantum dots, so that graphene quantum dots can produce more fluorescence quenching effect when detecting tetracycline antibiotics. The contrast of the double peak intensity can be increased when detecting quercetin. The doping of copper can cause electron transfer between the quantum dots and quercetin, so that the graphene quantum dots can detect quercetin. DETAILED DESCRIPTION - A nitrogen-copper doped graphene compound of formula (I), is new. INDEPENDENT CLAIMS are included for the following: preparation of compound (I), which involves mixing EDTA and copper chloride in water for dispersion, transferring to a reaction kettle for heating, and filtering reacted product; and a detection device, which comprises two light sources having emission wavelengths of 365 nm and 410 nm respectively, a platform on which filter paper is placed, a central sample area and two test areas arranged on the filter paper. The two test areas are located on both sides of the central sample area and communicated with the central sample area.