Arsenite oxidation and arsenate determination by the molybdene blue method
Arsenite oxidation and arsenate determination by the molybdene blue method
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DOI：
10.1016/s0039-9140(03)00274-1
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发表时间：
2003-11-04
期刊：
影响因子：
6.1
通讯作者：
Bollinger, JC
中科院分区：
文献类型：
--
作者：
Lenoble, V;Deluchat, V;Bollinger, JC
根据砷、磷性质的相似性，研究了利用砷蓝络合物比色法测定沃茨中低浓度砷的方法。确定了络合物形成时间、光照、温度和竞争性阴离子（硅酸盐和硫酸盐）对络合物形成的影响。在20 +/- 1 ℃下1小时内达到最佳复合物形成，在日光下显影时略有利。形成速率随反应温度的降低而下降，并且没有注意到任何测试的竞争性阴离子的影响（在花岗岩区域的天然沃茨中通常发现的浓度下）。该方法的检出限为20 μ g As（V）l（-1）。该方法简便、快速、灵敏，适用于现场分析，尤其适用于低磷、低有机质含量的沃茨。通过对砷的测定，比较了五种常用工业氧化剂对砷的氧化效率。H2 O2和MnO 2（s）不被认为是有效的氧化剂，因为高过量是确保As（III）氧化所必需的。NaOCl和KMnO 4是有前途的氧化剂，因为它们允许完全的亚砷酸盐氧化，NaOCl稍微过量，或者在KMnO 4的情况下甚至小于电子化学计量比。FeCl 3是这里测试的试剂中最有效的氧化剂。(C)2003 Elsevier B. V.保留所有权利。
Based on the similarity in properties of arsenate and phosphate, the colorimetric method using the molybdene blue complex was tested in order to determine low As(V) concentration in waters. The influence of complex formation time, daylight, temperature and competitive anions (silicate and sulphate) upon complex formation was determined. Optimal complex formation was reached in 1 h at 20 +/- 1 degreesC and was slightly favoured when developed in daylight. The formation rate declined with decreasing reaction temperature and no influence of any of the competitive anions tested (at concentrations usually found in natural waters of granitic areas) was noted. The detection limit of this method was 20 mug As(V) l(-1). This simple, fast and sensitive arsenic determination method is suitable for field analysis, especially for waters containing low levels of phosphate and organic matter. Through arsenate determination, this colorimetric method allowed the arsenite oxidation efficiency of five common industrial oxidants to be compared. H2O2 and MnO2(s) were not considered as effective oxidants as a high excess was necessary to ensure As(III) oxidation. NaOCl and KMnO4 were promising oxidants as they allowed complete arsenite oxidation with a small excess for NaOCl or even less than the electron stoichiometric ratio in the case of KMnO4. FeCl3 was the most effective oxidant among the reagents tested here. (C) 2003 Elsevier B.V. All rights reserved.