Microcolumn-based speciation analysis of thallium in soil and green cabbage
Microcolumn-based speciation analysis of thallium in soil and green cabbage
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土壤和卷心菜中铊的微柱形态分析
DOI：
10.1016/j.scitotenv.2018.02.147
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发表时间：
2018-07-15
影响因子：
9.8
通讯作者：
Baveye, Philippe C.
中科院分区：
文献类型：
--
作者：
Jia, Yanlong;Xiao, Tangfu;Baveye, Philippe C.
铊（Tl）是一种有毒的微量金属，其地球化学行为和生物效应受其在环境中的化学形态控制。然而，很少有人知道这种形态的铊在土壤和植物系统，直接影响食品供应的安全。在这种情况下，本研究的目的是制定一个有效的方法来分离和检测土壤和植物样品中的Tl（I）和Tl（III）物种。该方法包括在DTPA（乙二胺五乙酸）存在下，在填充有固定化8-羟基喹啉的微柱上选择性吸附Tl（I），然后通过DTPA增强的超声和听觉诱导提取，结合ICP-MS检测。该方法的特征在于，在10 mL样品中，Tl（I）和Tl（III）的LOD分别为0.037 μ g/L和0.18 μ g/L。用这种方法，研究的第二个目的是评估铊在盆栽和田间土壤和绿色卷心菜作物中的形态。结果表明，DTPA作用下的Tl主要以Tl（I）的形式存在于土壤中（>95%）。超积累植物绿色甘蓝中的Tl也主要以Tl（I）的形式存在（>90%）。本研究为绿色甘蓝主要从土壤中吸收Tl（I），并将其转运到地上器官中提供了直接证据。在土壤中，即使在化学环境促进氧化的表面，Tl（III）也被还原为Tl（I）。这一观测结果有助于理解土壤-植物系统中铊同位素分馏的机制。根据地球化学形态研究，可还原态是植物积累铊的主要来源。这些结果表明，在这项研究中提出的改进的分析方法提供了一个经济，简单，快速，灵敏的方法分离的铊存在于土壤中的痕量水平。(C)2018 Elsevier B. V.版权所有。
Thallium (Tl) is a toxic trace metal, whose geochemical behavior and biological effects are closely controlled by its chemical speciation in the environment. However, little tends to be known about this speciation of Tl in soil and plant systems that directly affect the safety of food supplies. In this context, the objective of the present study was to elaborate an efficient method to separate and detect Tl (I) and Tl(III) species for soil and plant samples. This method involves the selective adsorption of Tl(I) on microcolumns filled with immobilized oxine, in the presence of DTPA (cliethyleneffiaminepentaacetic acid), followed by DTPA-enhanced ultrasonic and hearing-induced extraction, coupled with ICP-MS detection. The method was characterized by a LOD of 0.037 mu g/L for Tl(I) and 0.18 mu g/L for Tl(III) in 10 mL samples. With this method, a second objective of the research was to assess the speciation of Tl in pot and field soils and in green cabbage crops. Experimental results suggest that DTPA exit-acted Tl was mainly present as Tl(I) in soils (>95%). Tl in hyperaccumulalor plant green cabbage was also mainly present as Tl(I) (>90%). With respect to Tl uptake in plants, this study provides direct evidence that green cabbage mainly takes up Tl(I) from soil, and transports it into the aboveground organs. In soils, Tl(III) is reduced to Tl(I) even at the surface where the chemical environment promotes oxidation. This observation is conducive to understanding the mechanisms of Tl isotope fractionation in the soil-plant system. Based on geochemical fraction studies, the reducible fraction was the main source of Tl getting accumulated by plants. These results indicate that the improved analytical method presented in this study offers an economical, simple, fast, and sensitive approach for the separation of Tl species present in soils at trace levels. (C) 2018 Elsevier B.V. All rights reserved.