MnO<sub>2</sub>共沉淀直接β计数测定小体积海水中的<sup>234</sup>Th

马嫱; 陈敏; 邱雨生; 黄奕普

MnO₂共沉淀直接β计数测定小体积海水中的²³⁴Th

1.
厦门大学, 海洋系, 福建, 厦门, 361005
2.
厦门大学, 海洋系, 福建, 厦门, 361005;厦门大学, 近海海洋环境科学国家重点实验室, 福建, 厦门, 361005

基金项目: 中国大洋矿产资源研究开发协会国际海底区域研究开发计划资助项目(DY1050204;DY1050201);国家自然科学基金资助项目(项目90411016)

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出版历程
- 收稿日期: 2005-01-21
- 修回日期: 2005-03-21

MnO₂ precipitation and direct beta counting technique for determining ²³⁴Th in small-volume seawater

1.
Department of Oceanography, Xiamen University, Xiamen 361005, China
2.
Department of Oceanography, Xiamen University, Xiamen 361005, China;State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China

摘要

摘要: 探讨了MnO₂共沉淀直接β计数测定小体积海水中²³⁴Th方法在固体闪烁α/β计数仪上实现的可能性,对实验流程空白、流程化学回收率、仪器探测效率、MnO₂共沉淀量对全程回收率的影响以及检测核素的特征性等进行了研究.结果表明,该方法具有稳定的流程空白和全程回收率、高的探测效率和化学回收率,且所检测核素与²³⁴Th的理论半衰期基本吻合.将该流程应用于亚热带北太平洋表层水中²³⁴Th的分析也得到了令人满意的结果.与传统方法相比,该方法具有流程简单、所用水样体积小、快速获得结果等特点,适合于船载分析,由此可实现高时空分辨率数据的获取,为海洋颗粒有机碳输出通量以及颗粒物迁移速率的研究提供了更好的分析手段.
- 海水 /
- ²³⁴Th /
- MnO₂共沉淀 /
- β计数
Abstract: A method for ²³⁴Th deter mination in small-volume seawater was established by using the alpha/bet a counter with scintillating solid detectors.This method is based on the coprecipitation of thorium with Mn oxides followed by direct beta counting of the precipitation.A series of experiments were conducted in order to examine the blank,chemical yield,detector efficiency of the procedure.Besides,the effect of the amount of MnO₂ precipitation on total yields was tested.Hal-flife determination was used to verify the reliability of the method.The results show that this procedure has stable blanks and total yields,high detector efficiencies and chemical yields.The half-life of the measuring nuclide is consistent with that of ²³⁴Th.This technique has been used to measure ²³⁴Th in surface seawater samples from the subtropical North Pacific.Comparing with previous classic methods,this new technique has the advantage of minimal sample volume,easier processing prior to beta counting,and suitable for ship-board analysis.By using this method for ²³⁴Th determination,much higher spatial and temporal resolution data can be obtained,and knowledge of POC export in the ocean may greatly be increased.
- seawater /
- ²³⁴Th /
- MnO₂ precipitation /
- beta counter

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参考文献(22)

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