Method for Ultratrace Level 241Am Determination in Large Soil Samples by Sector Field-Inductively Coupled Plasma Mass Spectrometry: With Emphasis on the Removal of Spectral Interferences and Matrix Effect

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• 作者：Zhongtang Wang ; Jian Zheng ; Liguo Cao ; Keiko Tagami ; Shigeo Uchida
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：July 19, 2016
• 年：2016
• 卷：88
• 期：14
• 页码：7387-7394
• 全文大小：493K
• 年卷期：0
• ISSN：1520-6882

文摘

A new method using sector field-inductively coupled plasma mass spectrometry (SF-ICPMS) was developed for the determination of ²⁴¹Am in large soil samples to provide realistic soil-plant transfer parameter data for dose assessment of nuclear waste disposal plans. We investigated four subjects: extraction behaviors of interfering elements (Bi, Tl, Hg, Pb, Hf, and Pt) on DGA resin (normal type, abbreviated as DGA-N); soil matrix element removal (Mg, Fe, Al, K, Na) using Fe(OH)₃, CaF₂, and CaC₂O₄ coprecipitations; Am and rare earth elements (REEs) separation on DGA-N and TEVA resins; and optimization of SF-ICPMS (equipped with a high efficiency nebulizer (HEN)) for Am determination. Our method utilized concentrated HNO₃ to leach Am from 2 to 20 g soil samples. The CaC₂O₄ coprecipitation was used to remove major metals in soil and followed by Am/interfering elements separation using the proposed UTEVA + DGA-N procedure. After a further separation of REEs on TEVA resin, ²⁴¹Am was determined by HEN-SF-ICPMS. This method eliminated the matrix effect in ICPMS ²⁴¹Am measurement for large soil samples. The high decontamination factors (DFs) of interfering elements enable their thorough removal, and in particular, the DF of Pu (7 × 10⁵) was the highest ever reported in ²⁴¹Am studies; thus, this method is capable of analyzing ²⁴¹Pu-contaminated Fukushima Daiichi Nuclear Power Plant (FDNPP) sourced soil samples. A low detection limit of 0.012 mBq g^–1 for ²⁴¹Am was achieved. The chemical recovery of Am (76–82%) was stable for soil samples. This method can be employed for the low level ²⁴¹Am determination in large size soil samples that are contaminated with ²⁴¹Pu.