Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
Agilent Technologies Co., Ltd (China), Beijing, China.
Rapid Commun Mass Spectrom. 2020 Apr 30;34(8):e8690. doi: 10.1002/rcm.8690.
An inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) instrument can be developed to determine Sr/ Sr ratios with an external precision better than 0.05% relative standard deviation (RSD) in "mass shift" mode without prior Sr purification. Previous studies suggested using CH F, N O, and SF as reaction gases for this method because a better reaction rate can be achieved with Sr than with O in the reaction cell. However, these gases are not commonly used in general chemistry laboratories, and processes using these gases are difficult to implement quickly due to regulations. We aim to develop a rapid method that can be applied to many samples for the accurate determination of Sr/ Sr isotope ratios with precision below 0.1% RSD (or approximately to the fourth decimal place).
We evaluated the accuracy and precision of Sr/ Sr ratios in certified reference materials and different rock types determined using ICP-MS/MS with O as the reaction gas in comparison with those determined using the multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) method.
This study showed that by using the ICP-MS/MS method, the Sr/ Sr ratios of BCR-2 and BHVO-2 do not vary significantly with and without prior Sr purification; when the Sr concentration of the measured solution is within the range of 60-350 ng/mL, there is no significant effect on the measured Sr/ Sr ratios. The results also showed that the Sr/ Sr ratios of 23 different rock types measured by ICP-MS/MS and MC-ICP-MS methods agree very well.
The precision of the Sr/ Sr ratio measured using ICP-MS/MS varies between 0.0001 and 0.0019 (2SD). This precision is less than that of the MC-ICP-MS method but is sufficient for certain applications, such as identifying Sr/ Sr ratios in different rock types. These results suggest that the developed ICP-MS/MS method has the potential for future studies involving the identification of Sr sources.
感应耦合等离子体质谱串联质谱仪（ICP-MS/MS）可在无需预先进行 Sr 纯化的情况下，以“质量偏移”模式测定 Sr/Sr 比值，其外部精密度优于 0.05%相对标准偏差（RSD）。先前的研究表明，由于在反应池中，Sr 比 O 具有更好的反应速率，因此可以使用 CHF、NO 和 SF 作为该方法的反应气体。然而，这些气体在普通化学实验室中并不常用，并且由于法规限制，使用这些气体的过程难以快速实施。我们旨在开发一种快速方法，该方法可应用于许多样品，以实现精密度低于 0.1%RSD（或精确到小数点后第四位）的准确 Sr/Sr 同位素比值测定。
我们评估了在使用 O 作为反应气体的 ICP-MS/MS 与使用多接收电感耦合等离子体质谱（MC-ICP-MS）方法测定的认证参考物质和不同岩石类型的 Sr/Sr 比值的准确性和精密度。
本研究表明，通过使用 ICP-MS/MS 方法，BCR-2 和 BHVO-2 的 Sr/Sr 比值在无需预先进行 Sr 纯化的情况下不会发生显著变化；当测量溶液中的 Sr 浓度在 60-350ng/mL 范围内时，对测量的 Sr/Sr 比值没有显著影响。结果还表明，使用 ICP-MS/MS 和 MC-ICP-MS 方法测定的 23 种不同岩石类型的 Sr/Sr 比值非常吻合。
使用 ICP-MS/MS 测定的 Sr/Sr 比值的精密度在 0.0001 到 0.0019（2SD）之间变化。该精密度小于 MC-ICP-MS 方法的精密度，但足以满足某些应用的需求，例如识别不同岩石类型中的 Sr/Sr 比值。这些结果表明，所开发的 ICP-MS/MS 方法有可能用于未来涉及识别 Sr 来源的研究。
