同位素双稀释剂计算软件(DSCAL)的开发及其地球化学应用

A new data reduction platform(DS_CAL)for double-spike technique and its application in geochemistry

二十一世纪以来,随着多接收电感耦合等离子体质谱仪(MC-ICP-MS)和热电离质谱仪(TIMS)的发展和广泛应用,多种非传统稳定同位素体系(Li、B、Mg、Ca、Mo、Cd、Fe和Zn等)的分析方法得到了快速发展,而仪器的质量分馏校正是进行准确同位素分析的关键因素之一。双稀释剂法被认为是最理想的仪器质量分馏校正方案,能够获得高精度的同位素比值。然而,复杂的计算推导和数据处理在一定程度上限制了双稀释剂法的使用和推广。在前人双稀释剂理论研究的基础上,本研究自主开发了双稀释剂数据处理平台(DSCAL,基于Microsoft Excel VBA)。该平台集合了测试数据的批量导入、目标元素参数的添加与修改、数据批量计算等操作,能够同时处理稳定同位素和放射性成因同位素体系的双稀释剂法数据计算,且不同实验室也能够根据所使用稀释剂的组成自主修改计算参数。本文还通过Mo同位素测试和计算实例,不仅显示出双稀释剂法具有高的测试精度,还展示了DSCAL在双稀释剂法数据处理计算中的便捷性与高效性。DSCAL能够应用于所有适用双稀释剂法计算的同位素体系,该平台的开发将有助于同位素双稀释剂技术的推广和发展。

This century has witnessed the improvement of multi-collector-inductively coupled plasma mass spectrometry(MC-ICP-MS) and thermal ionization mass spectrometry(TIMS), which led to the breakthrough in analytical methods for many non-traditional stable isotopes(e.g., Li, B, Mg, Ca, Mo, Cd, Fe and Zn). Accuracy of isotope measurement is dependent on proper correction methods for instrumental mass fractionation. The double-spike technique has been proposed as one of the most suitable correction methods for the precise and accurate measurement. However, complex mathematical calculations impede the application of this technique. This study designed a Microsoft Excel VBA based data reduction platform named "DSCAL" for processing of double-spike technique data. The platform can conduct batch data input, element addition and parameter modification, and batch calculation for data obtained with the double-spike technique. The platform also provides two calculation models for stable and radiogenic isotopes. In addition, the calculation parameters(including the double spike composition) of DSCAL can be flexibly modified. This study also shows an example of Mo isotope for the application of DSCAL. This technique can be applied to all isotope systems that are suitable for double-spike technique which will promote its extensive application to isotopic analysis.