Electrochemical Detection of Heavy Metals by Differential Pulse Anodic Stripping Voltammetry on Bismuth Thin Film Electrodes

• Main Authors: Yi-Chi Chiu, 邱義琦
• Other Authors: 顏溪成
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/gfha4b

碩士 === 國立臺灣大學 === 化學工程學研究所 === 105 === For trace metal analysis, electroanalytical methods offer several advantages over spectroscopies: simplicity, low cost and possibility of in-field application. Although the mercury thin film electrode and hanging mercury drop electrode are highly sensitive and selective, mercury is a highly toxic metal. Bismuth has been known as an environmentally friendly material which can be metabolized by human body, so nowadays bismuth thin film electrodes have become alternative material for electrochemical analysis. In this study, bismuth thin film electrodes were fabricated by electroplating bismuth on the glassy carbon electrode(GCE) in 0.1M acetate buffer solution (pH=4) containing 40ppm of Bi(III), and used in measuring of the concentration of Cd(II) by differential pulse anodic stripping voltammetry(DPASV). The effects of pre-electrodeposition potential, the concentration of Bi(III) in the analyte solution, and rotation of the working electrode have been investaged. The experimental results showed that the sensitivity of the electrode was increased about 76% with the pretreatment of glassy carbon electrodes by applying cyclic potential scans in 0.5M H2SO4. It was found that DPASV provided better Cd(II) detection in the analyte solution containing 1000ppb of Bi(III), and the best linear plot based on peak area in determination of 10 to 120ppb of Cd(II) occurred in the analyte solution containing 100ppb of Bi(III). The Bi thin film electrode on GCE offered good detection, even in non-deaerated solutions. From the investigation of pre-electrodeposition potential in DPASV, the maximum peak current was obtained at -1.1V (vs Ag/AgCl/KCl). It has been found in the experimental results that the preparation of Bi thin film electrode before anodic stripping voltammetry has been found unnecessarily, which can simplify the detection procedures. In the anodic stripping step, the electrode without rotation could keep the more stable current peaks than the electrode with rotation. The detection limit of Cd2+ is 0.2ppb.