title: The electron-transfer based interaction between transition metal ions and photoluminescent graphene quantum dots (GQDs): a platform for metal ion sensing.
abstract: The electron-transfer based quenching effect of commonly encountered transition metal ions on the photoluminescence of grapheme quantum dots (GQDs) was for the first time investigated, and was found to be associated with electron configuration of the individual metal ion. Ethylene diamine tetraacetic acid (EDTA), the metal ion chelator, can competitively interact with metal ions to recover the quenched photoluminescence of GQDs. Basically, metal ions with empty or completely filled d orbits could not quench the photoluminescence of GQDs, but this quenching effect was observed for the metal ions with partly filled d orbits. Based on the quenching-recovering strategy, a simple optical metal sensing platform was established by taking Ni(2+) as an example. Using the nickel ion-specific chelating reagent, dimethylglyoxime (DMG), to replace EDTA, a detection limit of 4.1 μM was obtained in standard solution. This proposed strategy does not need further functionalization of GQDs, facilitating the application for simple, fast and cost-effective screening of metal ions.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
authors.forename: Hongduan
authors.initials: H
authors.lastname: Huang
authors.forename: Lei
authors.initials: L
authors.lastname: Liao
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Mingjian
authors.initials: M
authors.lastname: Zou
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Na
authors.initials: N
authors.lastname: Li
mesh_terms: D002614:Chelating Agents / Q000737:chemistry; D060766:Drinking Water / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D004579:Electron Transport; D004583:Electrons; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D008027:Light; D049449:Luminescence; D009532:Nickel / Q000032:analysis*; D010091:Oximes / Q000737:chemistry; D045663:Quantum Dots; D028561:Transition Elements / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002614:Chelating Agents; D060766:Drinking Water; D010091:Oximes; D028561:Transition Elements; D014874:Water Pollutants, Chemical; C013501:dimethylglyoxime; D006108:Graphite; D009532:Nickel; D004492:Edetic Acid
keywords: Graphene quantum dots; Photoluminescence; Quenching; Transition metal ions