Anodic Stripping Voltammetric Determination Of As(â…¢) Using Metellic Nanoparticles Modified Glassy Carbon Electrode

Arsenic is a widely distributed element in the environment, which is a highly toxicsubstance, can cause carcinogenic, teratogenic, mutagenic effect to human and other livingorganisms, hence,it is of great significant to develop a accurate and sensitive method todetermine trace arsenic. Stripping voltammetry for heavy metal detection is characterized byits extremely high sensitivity, very low detection limit, fast and simple. Chemically modifiedelectrode is one of the hottest fields in electrochemistry, while nanomaterial has a series ofspecial optics, electrics, magnetics, dynamic and catalytic properties that are different fromtraditional materials. The combination of stripping voltammetry and nanomaterial canaccelarate electrochemical reaction rate, as well as improve the selectivity and sensitivity ofworking electrode. Therefore, the application of nanomaterial modified electrode to theanodic stripping voltammetric detection of Arsenic make it simple and easy to conduct, therunning cost is lower, and the method is of great practical use.The pollution, harm and detection of arsenic were introduced and the preparation andapplication of nanomaterial modified electrode were also reviewed in detail in the disse rtation.Gold nanoparticles and gold-palladium bimetallic nanoparticles were synthesized to modifiedelectrodes. The preparation and electrochemical properties were studied, and the response ofarsenic on gold nanoparticle modified electrode and gold-palladium nanoparticle modifiedelectrode were discussed. The main research works are shown as follows:1. Gold nanoparticles and gold-palladium bimetallic nanoparticles were synthesized usingchemical reduction method, UV-Vis spectrometer and transmission electron microscope wereused to characterize gold nanoparticles, while UV-Vis spectrometer, high resolutiontransmission electron microscope, scanning electron microscope, X-ray photoelectronspectroscopic and energetive diffraction spectra were applied to characterize gold-palladiumbimetallic nanoparticles. The electrochemical properties of nanomaterial modified electrodewere investigated in H2SO4solution using cyclic voltammetry. It was found that goldnanoparticles were spheric in shape with a diameter of20nm in average; gold-palladiumbimetallic nanoparticles present in core-shell structure, which contain both gold andpalladium; gold nanoparticles modified electrode exhibits macro gold electrode behavior, gold-palladium bimetallic nanoparticles modified electrode shows the behavior of both goldand palladium.2. A glassy carbon electrode modified with gold nanoparticles was used for voltammetricdetection of As(â…¢) in water. The effects of supporting electrolyte, stripping methods,deposition potential and time, frequency, increment and amplitude of square wavevoltammetry (SWV) were investigated, and the interference from Cu, Hg, Pb were alsodiscussed. Under the optimal conditions, arsenic's peak current and its concentration showedlinearity in the range of0.05-1ppb and1-15ppb, with a detection limit of0.025ppb, Cu, Hgand Pb interfere the detection of As in different way and extent.3. A glassy carbon electrode modified with gold-palladium bimetallic nanoparticles wasused to detect arsenic when using HNO3or acetate buffer solution as supporting electrolyte.The influences of deposition potential, SWV's frequency, amplitude and increment werediscussed, the interference from Cu, Hg, Pb, Cd, Zn, Mn and organic sulfide were also studied.In HNO3solution, the arsenic's peak current and its concentration showed linearity in therange of0.5-20ppb, with a detection limit of0.25ppb; while in acetate buffer solution, thelinear range was1-15ppb, the detection limit was0.5ppb. The detection of As was interferedby Cu, Hg and organic sulfide, but free of that from Pd, Cd, Zn, Mn.