▎ 摘　　要

Lead-doped graphene quantum dots modified with polyethylene glycol (PEG-Pb-GQDs) were one-step synthesized using biomass cane molasses as a green carbon source through simple hydrothermal method. The quantum yield (QY) of the PEG-Pb-GQDs can be as high as 30.31%, which is approximately three times that of graphene quantum dots (GQDs) without any modified, indicating that the doping of lead ions and the modification of polyethylene glycol (PEG) can realize the double-sided fluorescence enhancement effect. The as-prepared PEGPb-GQDs also exhibit stronger fluorescence, better stability and dispersion compared with lead doped graphene quantum dots (Pb-GQDs). The quasi-spherical PEG-Pb-GQDs were characterized by Fourier transforms infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) to prove the success of lead ions (Pb2+) doping and PEG passivation modification. Multiple metal ions including Fe3+, Cu2+, Ag+, Co2+, Ni2+, Pb2+ and Mn2+ and benzene sulfonic acid pigments including lemon yellow, quinoline yellow and sunset yellow can be detected by PEGPb-GQDs. Among the seven responsive metal ions, Fe3+ can be selectively detected under the condition of EDTA and thiourea as masking agent with a limit of detection (LOD) of 0.29 mu M for PEG-Pb-GQDs. Correspondingly, Cu2+ and Ag + can also be selectively detected by PEG-Pb-GQDs under appropriate masking agents. The benzene sulfonic acid pigments including lemon yellow, quinoline yellow and sunset yellow can also be selectively detected and the LOD were 0.067, 0.073 and 0.097 mu M, respectively. The quenching mechanisms were dynamic quenching for Fe3+, static quenching for Cu2+ and Ag+ and static quenching and fluorescence resonance energy transfer (FRET) for pigments.