Rapid Detection Of Hydrogen Sulfide And Heavy Metal Ions Based On Screen-printed Electrode

Electrochemical analysis method is a kind of instrument analysis methodbased on electrochemical properties of substances in solution, which has highsensitivity, good selectivity, high degree of automation, wide range of application.Screen-printed electrodes have the advantages such as flexible design, low cost andmass production, and have attracted more and more attention in the laboratory.Rapid detection of hydrogen sulfide （H2S）, Pb²⁺, Cu²⁺and other heavy metal ionsby electrochemical method based on screen-printed electrodes （SPE）.The mainly work of this thesis has two parts, as flowing:1. Rapid electrochemical detection of hydrogen sulfide based on screen-printed electrode.Cyclic voltammetry （CV） and differential pulse voltammetry （DPV） wereapplied to characterize the voltammetric response of hydrogen sulfide on thescreen-printed electrodes using potassium ferricyanide solution as the electronmediator. The electrochemical response revealed that the linear relationshipbetween the common logarithm of concentration and the oxidation peak currentcould be obtained in the rang of1×10-9¹Ã—10^-4mol L^-1with the detection limit of2.58×10^-10mol L^-1. This method was applied to the practical analysis of hydrogensulfide in the air with a satisfied test result. The result reflects that the method issimple, rapid, sensitive and has a low detection limit.2. Simultaneous detection of Cu（Ⅱ） and Pb（Ⅱ） by anodic strippingvoltammetry based on dithizone modified screen-printed electrodeDithizone was modified into screen-printed electrodes to simultaneousdetection of Cu²⁺and Pb²⁺by anodic stripping voltammetry （ASV） under theoptimum conditions of pH5.0, electrodeposition potential:^-1.1V,electrodeposition time:210s. And the voltammetric responses of anodic strippingof Cu²⁺and Pb²⁺on the modified electrode were characterized. The optimalconditions for the determination of Cu²⁺and Pb²⁺were determined by a series ofexperiments. The linear ranges of Cu²⁺and Pb²⁺were1×10^-101×10-5mol L^-1,1×10^-101×10-6mol L^-1, and the detection limits were0.35×10^-10mol L^-1, 0.41×10^-10mol L^-1, respectively. The method was used to detecting the content ofCu²⁺and Pb²⁺in different tea samples with recoveries of94.7¹02.5%,96.5¹00.9%, respectively.