Faghihi V, Meijer H A J, Gröning M
Center for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen (ESRIG), University of Groningen, The Netherlands.
Terrestrial Environment Laboratory, International Atomic Energy Agency (IAEA), Seibersdorf, Austria.
Rapid Commun Mass Spectrom. 2015 Aug 15;29(15):1351-6. doi: 10.1002/rcm.7232.
Oxygen and hydrogen stable isotopes are widely used tracers for studies on naturally occurring and laboratory mixtures of isotopically different waters. Although the mixing calculations are straightforward to perform, there are ample possibilities to make mistakes, especially when dealing with a large number of mixed fluids. To facilitate isotope mixing calculations and to avoid computational mistakes, a flexible tool to carry out these calculations is in demand.
We developed, in three independent efforts, spreadsheets to carry out the mixing calculations for a combination of waters with different isotopic compositions using the isotope mass balance equation. We validated our calculations by comparison of the results of the three spreadsheets for a large number of test calculations. For all the cases, we obtained identical results down to the 12(th) to 14(th) significant digit.
We present a user-friendly, thoroughly validated spreadsheet for calculating (2) H, (17) O and (18) O stable isotopic abundances and respective isotope delta values for mixtures of waters with arbitrary isotopic compositions. The spreadsheet allows the mixing of up to 10 different waters, of which up to five can be specified using their isotopic abundances and up to five others using their isotope delta values. The spreadsheet is implemented in Microsoft Excel and is freely available from our research groups' websites.
The present tool will be applicable in the production and characterization of singly and doubly labeled water (DLW) mother solutions, the analysis of isotope dilution measurements, the deduction of unknown isotope values of constituents for mixtures of natural waters, and many other applications.
氧和氢的稳定同位素是广泛用于研究天然存在的以及实验室中不同同位素组成水的混合物的示踪剂。尽管混合计算执行起来很简单，但仍有很多出错的可能性，尤其是在处理大量混合流体时。为便于进行同位素混合计算并避免计算错误，需要一种灵活的工具来进行这些计算。
我们通过三项独立的工作开发了电子表格，使用同位素质量平衡方程对具有不同同位素组成的水的组合进行混合计算。我们通过比较三个电子表格在大量测试计算中的结果来验证我们的计算。对于所有情况，我们在第12至14位有效数字上都得到了相同的结果。
我们展示了一个用户友好的、经过充分验证的电子表格，用于计算具有任意同位素组成的水混合物中（2）H、（17）O和（18）O的稳定同位素丰度以及各自的同位素δ值。该电子表格允许混合多达10种不同的水，其中最多5种可以使用它们的同位素丰度来指定，另外最多5种可以使用它们的同位素δ值来指定。该电子表格在Microsoft Excel中实现，可从我们研究小组的网站免费获取。
本工具将适用于单标记和双标记水（DLW）母液的生产和表征、同位素稀释测量分析、天然水混合物成分未知同位素值的推导以及许多其他应用。
