Detection Of Heavy Metals Lead And Cadmium Based On Anodic Stripping Voltammetry

Anodice Stripping Voltammetry（ASV）is an important electrochemical method for detecting heavy metals and it can analyse heavy metals qualitatively and quantitatively based on the peak potential and peak area of the stripping voltammetric curve.Because of the characteristics of high sensitivity(up to 1μg·L^-1),low cost,good reproducibility,ASV has been extensive used in water detection,drug composition and food analysis.In this paper,DVD-Ag electrode and glassy carbon electrode modified by bismuth trioxide-graphene composite material（Bi₂O₃@r GO）as well as The N-doped carbon nanotubes on the surface of stainless-steel mesh（N-CNTs@SS）electrode constructed by a new method and 3,4,9,10-perylene tetrabromoxylic diimide（PTCDI）-modified glassy carbon electrode were prepared.A method for simultaneous rapid determination lead ions and cadmium ions by anodic stripping voltammetry was established.After optimizing the test method,the lead ions and cadmium ions contents in actual samples（tap water and laboratory wastewater）were determined.Bismuth trioxide composite graphene（Bi₂O₃@r GO）modified electrode was prepared by solvothermal method,and heavy metal lead ions and cadmium ions were detected by anodic stripping voltammetry.The experimental results show that the dissolution response of lead ions and cadmium ions on unmodified glassy carbon electrode is much weaker than that of bismuth trioxide composite graphene modified electrode.And the prepared modified electrode is no less than the bismuth film electrode with mature technology.Within a certain concentration range,the dissolution current of lead ions and cadmium ions is linearly related to their concentration.When the enrichment time is 120 s,the detection limits of lead ions and cadmium ions are 0.02and 0.25μg·L^-1respectively,with excellent reproducibility consistent with the results of other detection methods.The DVD-Ag electrode was prepared from discarded DVD discs and the practicability of anodic stripping voltammetry for the detection of heavy metal ions was investigated.Anodic stripping voltammetry was carried out under the conditions of 0.01 M hydrochloric acid solution as supporting electrolyte,enrichment potential of-0.8 V and enrichment time of 118 s.The detection limits of lead ions and cadmium ions are 0.2μg·L^-1and 2.6μg·L^-1（S/N=3）,respectively.At the same time,I^-can promote the adsorption of metal ions on the electrode surface.The concentration of lead ions and cadmium ions in tap water was measured by standard sample addition method using this electrode,which shows that DVD-Ag electrode has certain practicability.The N-doped carbon nanotubes on the surface of stainless-steel mesh（N-CNTs@SS）electrode and 3,4,9,10-perylenetetracarboxylic diimide（PTCDI）-modified glassy carbon electrode constructed by a new method in this paper have proved that lead ions and cadmium ions also have excellent dissolution response on PTCDI-modified glassy carbon electrodes and have a linear relationship with ion concentration,which provides ideas and feasibility for enriching the types of membrane electrodes.It is proved that the N-doped carbon nanotubes on the surface of stainless-steel mesh（N-CNTs@SS）electrode can simultaneously detect the concentration of trace lead ions and cadmium ions and has good dissolution response to lead ions and cadmium ions,and is positively correlated with the ion concentration.