文章基本信息

标题：OPTIMIZING THE DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRY METHOD WITH A HANGING MERCURY ELECTRODE FOR THALLIUM (I) DETERMINATION IN THE PRESENCE OF LEAD (II) AND COPPER (II) FOR APPLICATION IN CONTAMINATED SOILS
本地全文：下载
作者：Yusniel Cruz-Hernández ; Mario Villalobos ; José Luz González-Chavez 等
期刊名称：Revista Internacional de Contaminación Ambiental
印刷版ISSN：0188-4999
出版年度：2019
卷号：35
期号：2
页码：481-494
DOI：10.20937/RICA.2019.35.02.18
出版社：Centro de Ciencias de la Atmósfera
摘要：The conditions that allow thallium (I) determination in the presence of lead (II) and copper (II) were optimized without prior separation of these cations, using a previously developed differential pulse anodic stripping voltammetry (DPASV) method, with a hanging mercury drop working electrode (HMDE) and a Ag/AgCl reference electrode. Unfortunately, the electrochemical activity of lead (II) interferes with this determination, but the addition of 0.1 M EDTA complexing agent (at pH = 4.6) causes a shift in the Pb(II) peak to more negative values, making it possible to quantify Tl(I) in its presence at an optimal deposition potential of –0.550 V. However, the Cu(II) reduction peak, which is normally found far away from that of Tl(I), is also shifted when complexed with EDTA, approaching the Tl(I) peak and becoming an interfering ion. The deposition time and scan rate that were found optimal for the determination were 30 s and 10 mV/s, respectively. Under these conditions it was found that maximum concentration ratios for Pb(II)/Tl(I) and Cu(II)/Tl(I) of 2000 and 400, respectively, did not show interference thus duplicating and quadruplicating the concentrations of Pb(II) and Cu(II), respectively above which interference with Tl(I) occurs, as compared to the standard method published. The proposed methodology has a detection limit of 2 μg/L, a quantification limit of 7 μg/L, and a linear range between 2.3 and 20 μg/L. Enriched Tl solutions of 0.5, 2.5 and 9 μg/L showed excellent recoveries. The methodology was applied to extractions of contaminated soil samples with Tl contents from 0.05 to 3.2 mg/kg.
关键词：voltamperometric; interference; trace analysis; thallium; EDTA; soil samples
其他关键词：voltamperometric;interference;trace analysis;thallium;EDTA;soil samples;voltamperometric;interference;trace analysis;thallium;EDTA;soil samples