阴离子交换树脂分离富集/电感耦合等离子体质谱测定珊瑚中铅的同位素组成

在自制微型离子交换柱的基础上,建立了阴离子交换树脂AG1-X8分离富集珊瑚中痕量元素Pb的前处理方法,并使用高分辨电感耦合等离子体质谱(HR-ICP-MS)测定了海南橙黄滨珊瑚(porites lutea)样品中的Pb同位素比值。从全程空白值、洗脱曲线、回收率和基体分离情况等方面考察了不同洗脱剂的洗脱效果,结果表明,采用0.50 mol/L HNO3时的洗脱效果最好,方法的全程空白值为18 pg,Pb的回收率为99.6%,在洗脱过程中无拖尾现象,且能与Ca、Sr、Mg、Fe、Mn、Zn、Ba和U等珊瑚中的基体元素成功分离,对上述基体元素的去除率均能达到99.8%以上。使用该方法测得海南珊瑚样品中的207Pb/206Pb、208Pb/206Pb比值分别为0.850 5、2.087 0,相对标准偏差(RSDs,n=21)分别为0.12%和0.11%。该法质量控制良好,表明建立的AG1-X8阴离子交换树脂分离富集/HR-ICP-MS测定珊瑚中Pb的同位素组成的方法可靠,可推广应用于其它复杂样品中铅同位素组成的测定。

Determination of Lead Isotopic Ratios in Corals by Anion Exchange Resin Technique and High Resolution Inductively

A pretreatment method to enrich trace element Pb in corals was established with AG1-X8 anion exchange resin and self-made PTFE micro column,then Pb isotopic ratios in Hainan corals(porites lutea) in China was measured by high-resolution inductively coupled plasma mass spectrometry(HR-ICP-MS).Several parameters including procedural blank,elution curve,Pb recovery and matrix separation were compared among four different eluents,and the results showed 0.50 mol/L HNO3 was the best eluent,of which the procedural blank was 18 pg,and recovery of Pb was 99.6%,besides,there was no tailing observed and more than 99.8% of the matrix elements in corals such as Ca,Sr,Mg,Fe,Mn,U,Ba as well as Zn could be well separated from Pb during the eluting process.After eluted with 0.50 mol/L HNO3,207Pb/206Pb and 208Pb/206Pb in Hainan corals was determined to be 0.850 5 and 2.087 0,with RSDs(n=21) of 0.12% and 0.11%,respectively.All the values were located between two warning lines,which indicated the quality control was acceptable and the pretreatment method was reliable.The method established could be applied in the determination of Pb isotopic ratios in corals and other similar samples.