锆石Hf同位素：MC-ICP-MS和LA-MC-ICP-MS分析结果的比较

采用单柱离子色谱法高效提取锆石中的Hf元素，用MC—ICP—MS测定锆石Hf同位素组成。三个锆石样品及其平行样的分析结果显示，同一样品的Hf同位素组成在误差范围内高度一致，表明用单柱离子交换色谱法能够有效分离锆石的Hf元素，可以保证Hf同位素分析结果的再现。对比MC—ICP—MS和LA—MC—ICP—MS分析结果发现，同一样品锆石的Hf同位素在误差范围内一致，具有很好的可对比性。但对颗粒较小的锆石，缩小激光束斑使之不超出锆石颗粒的范围，能够获得更好的结果。

A comparison of zircon Hf isotope analyses by MC-ICP-MS and LA-MC-ICP-MS

The single ion-exchange chromatography modified from Goolaerts et al.(2004)was utilized to separate Hf from three zircon samples and then Hf isotopes were determined by MC-ICP-MS.The duplicate analyses for each zircon samples yielded consistent ~(176) Hf/~(177) Hf ratios within error.This means that the single ion-exchange chromatography is an efficient method for separatiun of zircon Hf and the Hf isotopic compositions in the zircons from one rock sample can be reproduced by MC-ICP-MS.In addition,the consisteut Hf isotopic compositions within erro,can be produced by LA-MC-ICP-MS.For fine-grained zircons,however,more precise Hf isotopic ratios can be obtained by LA-MC-ICP-MS if the laser beam is reduced to fit the grain-size of zircons.