▎ 摘　　要

NOVELTY - Method for the detection of multiple heavy metal ions by a lead-doped polyethylene glycol (PEG) passivated graphene quantum dot fluorescent probe, involves: (a) dissolving cane molasses in deionized water, and adding lead(II) acetate solution; (b) ultrasonically processing and centrifuging, taking the supernatant into a reaction kettle, reacting, and filtering after cooling to obtain a lead-doped graphene quantum dot stock solution; (c) diluting it to 2 ml with analytically pure polyethylene glycol passivation agent; and (d) adding with or without adding a masking agent, adding any metal ion containing ferric ion, copper(II) ions, silver ion, cobalt ion, nickel ions, manganese ion and lead ions or a solution to be tested containing multiple metal ions, diluting the solution to 5 ml with analytical grade polyethylene glycol passivator, shaking, and leaving to stand for 5 minutes, and calculating the content of heavy metal ions from the results of fluorescence intensity. USE - Method for the detection of multiple heavy metal ions by a lead-doped polyethylene glycol (PEG) passivated graphene quantum dot fluorescent probe used in nano medicine, biological imaging, biological sensing and chemical sensing fields. ADVANTAGE - The method has rapid detection speed, high detection sensitivity, and low detection limit. DETAILED DESCRIPTION - Method for the detection of multiple heavy metal ions by a lead-doped polyethylene glycol (PEG) passivated graphene quantum dot fluorescent probe, involves: (a) dissolving 1.5-2 ml of cane molasses in 25-30 ml of deionized water, and then adding 1-3 mL of lead(II) acetate solution with a concentration of 0.1 mol/l; (b) ultrasonically processing and centrifuging the solution obtained in step (a), taking 20-25 ml of the supernatant into a 30 ml reaction kettle lined with PTFE, reacting in an oven at 190℃ for 20-24 hours, and filtering after cooling to obtain a lead-doped graphene quantum dot stock solution; (c) taking 100-200 μl of the lead-doped graphene quantum dot stock solution obtained in step (b), diluting it to 2 ml with analytically pure polyethylene glycol passivation agent, to obtain a lead-doped polyethylene glycol passivated graphene quantum dot solution (PEG-Pb-GQDs) solution, where the lead-doped polyethylene glycol passivated graphene quantum dot has a spherical shape, an average particle size of 1-2 nm, and a crystal plane spacing of 0.21 nm; and (d) adding the PEG-Pb-GQDs solution obtained in step (c) with or without adding a masking agent with a total volume of 600-800 μl and a concentration of 0.1 mol/l, adding any metal ion containing ferric ion, copper(II) ions, silver ion, cobalt ion, nickel ions, manganese ion and lead ions or a solution to be tested containing multiple metal ions, diluting the solution to 5 ml with analytical grade polyethylene glycol passivator, shaking well, and leaving to stand for 5 minutes, putting the solution into the cuvette of the VARIAN spectrofluorometer, choosing a voltage of 550 V, performing the fluorescence spectrum test under the test conditions with excitation and emission slits of 5 nm and excitation wavelength of 350-400 nm respectively, and calculating the content of heavy metal ions from the results of fluorescence intensity. The polyethylene glycol passivating agent is one or more of polyethylene glycol-200, polyethylene glycol-400 and polyethylene glycol-600. The masking agent is two or more of ethylenediaminetetraacetic acid, thiourea, sodium fluoride and potassium thiocyanate.