Separation and Quantification of Tl(I) and Tl(III) in Fresh Water Samples
Separation and Quantification of Tl(I) and Tl(III) in Fresh Water Samples
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DOI：
10.1080/10934520600655747
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发表时间：
2006-06
期刊：
影响因子：
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通讯作者：
U. Karlsson;A. Düker;S. Karlsson
中科院分区：
文献类型：
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作者：
U. Karlsson;A. Düker;S. Karlsson
根据Coetzee等人设计的改进方法，采用Tl3+与DTPA （penta-carboxymethyl- diethetriamine）络合，在阳离子交换柱上分离，用IC-ICP-MS测定了铊的两个氧化态Tl(I)和Tl（III）。为了避免在运行过程中分离效率的不断降低和分辨率的损失，用HCl代替HNO3进行梯度洗脱。用超声波喷雾器代替v型槽喷雾器，可将Tl(I)和Tl（III）的检出限分别从25 ng/L和3.0 ng/L降低到9.0 ng/L和0.7 ng/L，足以满足许多淡水系统的检测要求。Tl（III）在酸性溶液中的稳定性与浓度有关，Tl（III）的初始还原率很高。样品暴露于光下进一步提高了还原率。在含有1 μg/L Tl（III）的样品中加入DTPA （0.01 mM）和酸（HNO3, 1%），可以稳定Tl（III）含量至少48小时。现场样品分析表明，仅酸化不足以维持Tl(I)和Tl（III）的原始分布。内标（加入标准品）和用非离子内标（11B）对分析信号（205Tl）进行校正，得到了Tl(I)和Tl（III）的几乎定量回收率。提出了一种现场样品制备方案，包括取样、储存和分析前处理。
The two oxidation states of thallium, Tl(I) and Tl(III), were quantified by IC-ICP-MS using complexation of Tl3+ with DTPA (penta-carboxymethyl-diethylenetriamine) and separation on a cation exchange column according to a modification of the method devised by Coetzee et al. In order to avoid successively lowered separation efficiency and loss of resolution during a run, a gradient elution was made using HCl instead of HNO3. With an ultrasonic nebuliser instead of a V-groove nebuliser the limit of detection for Tl(I) and Tl(III) could be lowered from 25 ng/L and 3.0 ng/L to 9.0 ng/L and 0.7 ng/L, respectively, which is adequate for many fresh water systems. The stability of Tl(III) in acidic solutions was found to be concentration dependent, with an initially high reduction rate of Tl(III). Exposure of the sample to light further increased the reduction rate. Addition of DTPA (0.01 mM) and acid (HNO3, 1%) to a sample with 1 μg/L Tl(III) stabilised the Tl(III) content for at least 48 h. Analysis of field samples showed that only acidification is inadequate to maintain the original distribution of Tl(I) and Tl(III). Internal calibration (standard addition) and correction of the analytical signal (205Tl) with a non-ionic internal standard (11B) yielded almost quantitative recoveries of both Tl(I) and Tl(III). A scheme for field sample preparation is proposed, including sampling, storage and pre-analysis treatment.