title: Highly sensitive visual detection of copper (II) using water-soluble azide-functionalized gold nanoparticles and silver enhancement.
abstract: A high-sensitive method for the visual detection of copper ions in aqueous solution is developed. The method is based on copper ion-catalyzed 'click' reaction between the water-soluble azide-functionalized gold nanoparticles (AuNPs) and alkyne-modified glass slide. The PEG linker was employed as a stabilizing component along with the terminal azide group to keep the AuNPs stably dispersed in water without the assistance of any organic solvent. In the presence of copper ions, the AuNPs are 'clicked' on the slide, and the darkness of the AuNPs in the sample spot is promoted by silver enhancement process. Only a tiny amount of sample (10 μl) is needed with the detectable concentration down to 62 pM by the commonly used flatbed scanner, which is 2-3 orders of magnitude lower than those in previous reports. The selectivity relative to other potentially interfering ions and the applicability in real samples, human serum and tap water, have also been evaluated. Our method has a good potential in point-of-use applications and environment surveys.
authors.affiliation: Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, PR China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, PR China.
authors.forename: Qiuling
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, PR China. Electronic address: xfang@iccas.ac.cn.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Fang
mesh_terms: D001386:Azides / Q000737:chemistry*; D015374:Biosensing Techniques; D057930:Click Chemistry; D003124:Colorimetry / Q000379:methods; D003300:Copper / Q000032:analysis* / Q000097:blood*; D060766:Drinking Water / Q000032:analysis; D006046:Gold / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D001386:Azides; D060766:Drinking Water; D014867:Water; D012834:Silver; D006046:Gold; D003300:Copper
keywords: Click chemistry; Copper ions; Naked eye detection; Silver enhancement