Preservation of co-occurring As, Sb and Se species in water samples with EDTA and acidification
Preservation of co-occurring As, Sb and Se species in water samples with EDTA and acidification
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使用 EDTA 和酸化保存水样中共存的 As、Sb 和 Se 物质
DOI：
10.1144/geochem2015-369
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Pichler
中科院分区：
文献类型：
--
作者：
Pichler
研究了以下氧化还原对的同时保存：As（III，V），Sb（III，V）和Se（IV，VI）。在11周的时间段内，在具有不同溶解氧含量的水样中评估这三种氧化还原对的稳定性，即，地下水、湖水和河水。将高浓度的Fe（25.0 mg L-1）和Mn（25.0 mg L-1）添加到每个不同的基质中以模拟富Fe和Mn的环境。除了天然浓度外，每个样品还加入了5.0 μg L−1As（III和V）和Sb（III和V）以及15.0 μg L− 1 Se（IV和VI）。作为潜在的保存策略，单独的EDTA和EDTA与HCl，HNO 3，甲酸或乙酸的组合进行了研究，并与未保存的样品进行了比较。此外，保存的样品在4°C下避光储存，而未保存的样品在室温下避光储存。结果表明，添加EDTA并酸化至pH 3成功地将所有三种氧化还原对在4°C下在黑暗中储存至少11周。EDTA单独（pH = 6）未能保存的As和Sb的物种，虽然它成功地保存了硒物种。首先，根据对未保存样品的观察，得出结论，在中性pH下，Sb（III）比As（III）和Se（IV）更容易被氧化，并且Se物种通常最稳定。Fe-（氧）氢氧化物和可能的Mn-（氧）氢氧化物在未保存的样品中的形成也允许相对吸附行为的估计。As（III）、Sb（III）、Se（IV）和As（V）对Fe-（oxy）hydroxide和Mn-（oxy）hydroxide表现出强吸附亲和力，这可能是由于它们都形成内球络合物，而Sb（V）和Se（VI）很少吸附，因为它们形成外球络合物，因此通过弱静电吸附结合。锑（III）可以与EDTA螯合，并根据pH值形成几种络合物。Sb（III）Y−（Y = EDTA）最稳定的物种存在于pH值1.8至3.0的范围内。另一方面，Sb（V）显然不与EDTA螯合，因此在此pH范围内应主要以Sb（OH）6−和少量Sb（OH）5的形式存在。
The simultaneous preservation of the following redox couples was studied: As(III, V), Sb(III, V) and Se(IV, VI). Over a time period of 11 weeks the stability of these three redox couples was assessed in water samples with different dissolved oxygen content, i.e., groundwater, lake water and river water. High concentrations of Fe (25.0 mg L−1) and Mn (25.0 mg L−1) were added to each of the different matrices to simulate a Fe and Mn rich environment. In addition to their natural concentration, each sample was spiked with 5.0 μg L−1As(III and V) and Sb(III and V) and 15.0 μg L−1Se(IV and VI). As potential preservation strategies, EDTA alone and EDTA combined with HCl, HNO3, formic acid or acetic acid were investigated and compared to unpreserved samples. In addition, preserved samples were stored at 4°C in the dark, while unpreserved samples were stored at room temperature in the presence of light. The results showed that the addition of EDTA combined with acidification to a pH of 3 successfully preserved all three redox couples for at least 11 weeks stored at 4°C in the dark. EDTA alone (pH = 6) failed to preserve the As and Sb species, although it successfully preserved the Se species. Primarily based on observations made for the unpreserved samples, it was concluded that Sb(III) could be oxidized easier than As(III) and Se(IV) at neutral pH, and that the Se species in general were most stable. The formation of Fe-(oxy) hydroxide and possibly Mn-(oxy) hydroxide in the unpreserved samples also allowed an estimation of the relative adsorption behaviour. Arsenic(III), Sb(III), Se(IV)) and As(V) showed a strong adsorption affinity for Fe-(oxy) hydroxide and Mn-(oxy) hydroxide probably due to the fact that they all form inner sphere complexes, whereas Sb(V) and Se(VI) rarely adsorbed because they form outer sphere complexes and thus bond via weak electrostatic adsorption. Antimony(III) could chelate with EDTA and formed several complexes according to pH. The most stable species of Sb(III)Y−(Y = EDTA) existed at a pH range of 1.8 to 3.0. Apparently Sb(V), on the other hand, did not chelate with EDTA and thus should exist mainly in the form of Sb(OH)6−and minor Sb(OH)5in this pH range.
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影响因子：
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影响因子：
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DOI：
--
发表时间：
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期刊：
影响因子：
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