title: Non-conductive nanomaterial enhanced electrochemical response in stripping voltammetry: The use of nanostructured magnesium silicate hollow spheres for heavy metal ions detection.
abstract: Nanostructured magnesium silicate hollow spheres, one kind of non-conductive nanomaterials, were used in heavy metal ions (HMIs) detection with enhanced performance for the first time. The detailed study of the enhancing electrochemical response in stripping voltammetry for simultaneous detection of ultratrace Cd(2+), Pb(2+), Cu(2+) and Hg(2+) was described. Electrochemical properties of modified electrodes were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The operational parameters which have influence on the deposition and stripping of metal ions, such as supporting electrolytes, pH value, and deposition time were carefully studied. The anodic stripping voltammetric performance toward HMIs was evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The detection limits achieved (0.186nM, 0.247nM, 0.169nM and 0.375nM for Cd(2+), Pb(2+), Cu(2+) and Hg(2+)) are much lower than the guideline values in drinking water given by the World Health Organization (WHO). In addition, the interference and stability of the modified electrode were also investigated under the optimized conditions. An interesting phenomenon of mutual interference between different metal ions was observed. Most importantly, the sensitivity of Pb(2+) increased in the presence of certain concentrations of other metal ions, such as Cd(2+), Cu(2+) and Hg(2+) both individually and simultaneously. The proposed electrochemical sensing method is thus expected to open new opportunities to broaden the use of SWASV in analysis for detecting HMIs in the environment.
authors.affiliation: Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, PR China.
authors.forename: Ren-Xia
authors.initials: RX
authors.lastname: Xu
authors.forename: Xin-Yao
authors.initials: XY
authors.lastname: Yu
authors.forename: Chao
authors.initials: C
authors.lastname: Gao
authors.forename: Yu-Jing
authors.initials: YJ
authors.lastname: Jiang
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Han
authors.forename: Jin-Huai
authors.initials: JH
authors.lastname: Liu
authors.forename: Xing-Jiu
authors.initials: XJ
authors.lastname: Huang
mesh_terms: D002104:Cadmium / Q000032:analysis; D002413:Cations, Divalent / Q000032:analysis*; D003300:Copper / Q000032:analysis; D004563:Electrochemistry / Q000379:methods*; D017736:Ion-Selective Electrodes; D007854:Lead / Q000032:analysis; D017633:Magnesium Silicates / Q000737:chemistry; D008628:Mercury / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D054118:Nanospheres; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D002413:Cations, Divalent; D017633:Magnesium Silicates; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; C005013:Florisil; D007854:Lead; D003300:Copper; D008628:Mercury
keywords: Electrochemical detection; Heavy metal ions; Hollow spheres; Nanostructured magnesium silicate; Stripping voltammetry