▎ 摘　　要

NOVELTY - Preparing graphene quantum dot fast detecting pigment involves dissolving 1.5-2 ml sugarcane molasses in 25-30 ml deionized water, adding or not adding lead(II) acetate solution with a concentration of 0.1mol/L solution. The obtained solution is sonicated and centrifuged, and 20.0-25.0 mL of the supernatant is placed in a 30 mL reaction kettle lined with polytetrafluoroethylene, reacted in an oven at 170-200 ℃ for 20-28 hours, and filtered after cooling to obtain graphene quantum dot stock solution or lead-doped graphene quantum dot stock solution. 100-150 μL of the graphene quantum dot stock solution, and diluted it to 2 mL with ultrapure water or analytically pure polyethylene glycol to obtain graphene quantum dots (GQDs) solution or polyethylene glycol passivation modified graphene quantum dots (PEG-GQDs) solution. The pigment content is calculated from the change of fluorescence intensity. USE - Method for preparing graphene quantum dot fast detecting pigment in food additive based on sugarcane molasses. ADVANTAGE - The method enables providing an economic, portable, accurate and fast detecting lemon yellow in food additive, quinoline yellow and sunset yellow pigment method with strong selectivity, high sensitivity, fast detection speed, which is used in food safety monitoring field. DETAILED DESCRIPTION - Preparing graphene quantum dot fast detecting pigment involves dissolving 1.5-2 ml sugarcane molasses in 25-30 ml deionized water, adding or not adding lead(II) acetate solution with a concentration of 0.1mol/L solution. The obtained solution is sonicated and centrifuged, and 20.0-25.0 mL of the supernatant is placed in a 30 mL reaction kettle lined with polytetrafluoroethylene, reacted in an oven at 170-200 ℃ for 20-28 hours, and filtered after cooling to obtain graphene quantum dot stock solution or lead-doped graphene quantum dot stock solution. 100-150 μL of the graphene quantum dot stock solution, and diluted it to 2 mL with ultrapure water or analytically pure polyethylene glycol to obtain graphene quantum dots (GQDs) solution or polyethylene glycol passivation modified graphene quantum dots (PEG-GQDs) solution. The lead-doped graphene quantum dots (Pb-GQDs) solution or the lead-doped polyethylene glycol passivated graphene quantum dots (PEG-Pb-GQDs) solution are obtained, respectively. Four kinds of graphene quantum dot solutions of GQDs, PEG-GQDs, Pb-GQDs and PEG-Pb-GQDs are added containing any one of tartrazine, quinoline yellow and sunset yellow pigments or solutions containing multiple pigments to be tested. The pigment content is calculated from the change of fluorescence intensity. The polyethylene glycol-based passivating agent is one or more of polyethylene glycol-200, polyethylene glycol-400, and polyethylene glycol-600.