Rb-Sr age dating is a pillar of isotope geochronology and has been used to address numerous questions within geosciences as well as other fields, such as biology and anthropology. There are traditionally two main methods for producing Rb-Sr age dates — either sample dissolution and wet chemistry or via in situ techniques such as laser ablation. While wet chemistry can potentially yield the best precision, it is extremely slow and laborious. By contrast, in situ techniques are much faster but lack high precision. For both methodologies, care must be taken to separate out the isobaric interference of 87Sr from 87Rb.
Triple quadrupole ICP-MS has been widely used for Rb-Sr age dating. The presence of a collision/reaction cell allows separation of 87Sr from 87Rb. However, the new Thermo Scientific Neoma MS/MS MC-ICP-MS has the potential to take Rb-Sr age dating to the next level. With its patented collision/reaction cell and magnetic sector-based pre-cell mass filter coupled to its 11-cup multi-collector array, Neoma MS/MS MC-ICP-MS offers high precision and rapid in situ Rb-Sr age dating.
A new application note demonstrates that Neoma MS/MS MC-ICP-MS can produce Rb-Sr age dates with as good as 0.6% precision, almost an order of magnitude better than traditional TQ-ICP-MS, and almost as good as much slower wet chemistry approaches coupled to TIMS.
What’s more, the application note shows how Neoma MS/MS MC-ICP-MS can provide unparalleled levels of detail for Rb-Sr dating. Due to the static nature of the measure, several 1-second integrations can be used to generate an isochron. Therefore, it is possible to see distinct Rb-Sr age dates within a single laser ablation spot. This has enormous potential for mapping Rb-Sr age dates across grains and can be used to better characterize complex closure events within an individual crystal.
For more information and to read the application note and related pieces, visit www.thermofisher.com/ms-ms.
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