中华医学超声杂志

应用化学 ›› 2011, Vol. 28 ›› Issue (05): 597-601.DOI: 10.3724/SP.J.1095.2011.00423

• 研究论文 • 上一篇    下一篇

修饰铂电极上Bi(Ш)的示波双电位滴定法

齐蕾1,齐同喜2*   

  1. (1.南京大学化学化工学院 南京；2.山东理工大学化学工程学院 淄博 255049)
  • 收稿日期:2010-07-22 修回日期:2010-08-31 出版日期:2011-05-10 发布日期:2011-05-10
  • 通讯作者: 齐同喜，副教授; Tel:0533-2781925-2; Fax:0533-2781664; E-mail:qtx@sdut.edu.cn; 研究方向：电分析化学
  • 作者简介: 南京大学在读博士,主要从事物理化学研究.
  • 基金资助:
    山东省自然科学基金资助项目(Y2009B07)

Oscillo-Potentiometric Titration of Bismuth(Ⅲ) Using Modified Platinum Electrode

QI Lei1, QI Tongxi2*   

  1. (1. School of Chemistry and Chemical Engineering,Nanjing University,Nanjing；
    2.College of Chemistry and Chemical Engineering,Shandong University
    of Science and Engineering,Zibo 255049)
  • Received:2010-07-22 Revised:2010-08-31 Published:2011-05-10 Online:2011-05-10
  • Contact: qi tongxi
  • About author: Ph.D student in Nanjing University,major in physical chemistry

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摘要：

制备了Bi(Ⅲ)修饰铂电极，用循环伏安法表征了Bi(Ⅲ)在电极上的吸附特性，探讨了电极的响应机理。 通过优化实验条件，建立了一种测定Bi(Ⅲ)的示波双电位滴定法。 在0.1 mol/L的硝酸溶液中(pH=1.0)，用制备的修饰铂电极作为双指示电极，以EDTA标准溶液滴定Bi(Ⅲ)，利用示波器屏幕上荧光点的显著最大位移指示滴定终点。 Bi(Ⅲ)在1.19×10-4～1.44×10-2 mol/L时，回收率为99.8%～100.1%，检出限(S/N=3)为1.0×10-4 mol/L。 该修饰电极具有良好的稳定性和重现性，在含有1.0×10-2 mol/L Bi(Ⅲ)的溶液中，连续7次测定，所得终点电位值均在100 mV左右，其相对标准偏差(RSD)为0.04%。 应用该方法测定含铋样品，RSD值(n=7)小于0.25%，回收率为99.5%～100.5%，测定结果与指示剂法测定值相符。

关键词: 示波分析,双电位滴定法, 修饰铂电极, Bi(Ш),EDTA

Abstract:

Bi(Ⅲ) modified Pt-electrode was prepared and the adsorption character of Bi(Ⅲ) on the electrode was studied by cyclic voltammetry. The mechanism of electrode response was discussed. A method using oscillo-potentiometry for the titration of Bi(Ⅲ) was described. In 0.1 mol/L nitric acid solution(pH=1.0), Bi(Ⅲ) was titrated with EDTA, and two modified Pt-electrodes were used as bi-indicator electrode system. The end point of titration was determined by an abrupt maximum displacement of the fluorescence spot observed on the screen of the cathodic oscillograph. When Bi(Ⅲ) content was in the range of 1.19×10-4～1.44×10-2 mol/L, the recovery was in the range of 99.8%～100.1% and the detection limit was 1.0×10-4 mol/L(S/N=3). Furthermore, the modified electrode showed excellent stability and reproducibility. In 1.0×10-2 mol/L Bi(Ⅲ) solution, the values of end point potentials obtained from 7 continuous determinations were all around 100 mV, and the relative standard deviation(RSD) was 0.04%. Moreover, the proposed method has been used in the determination of Bi(Ⅲ) contained in samples with recoveries of 99.5%～100.5% and RSD(n=7) less than 0.25%, which are in accordance with the indicator method.

Key words: oscillography analysis, double potentiometric titration, modified Pt-electrode, Bi(Ш), EDTA

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