The in-situ Sr isotope determination of solid samples has the advantages of high spatial resolution and convenient and rapid sample preparation. However, due to the lack of column chemistry separation of matrix elements from Sr, the interference correction (especially the isobaric interference from ⁸⁷Rb on ⁸⁷Sr) becomes a big issue for high precise in-situ Sr isotope analytical results. In this study, we evaluated the influence of isobaric interference systematically and adopted an improved strategy for isobaric interference correction of Rb. Specifically, as an external standard for data calibration, an in-house silicate standard (Rb-std) was fused from pure oxide powders. The new standard (Rb-std) shows very low contents of Sr (<1 ppm), Yb (<0.09 ppm) and Er (<0.05 ppm), which directly avoid the trouble of interference of doubly charged ions and isobar, when we determinate the mass fractionation factors of Rb (βRb). Our improved method can provide more accurate data than previous researches, in which the mass fractionation were calculated from an external reference material StHs6/80-G with high Rb (30.07 ppm), Sr (482 ppm), Yb (1.13 ppm) and Er (1.18 ppm). Then, these βRb from Rb-std were applied by linear interpolation to the unknown samples for correction of ⁸⁷Rb on ⁸⁷Sr. The analytical results of serial international reference materials (BIR-1G, BCR-2G, BHVO-2G, T1-G and ATHO-G) demonstrate that our improved method can raise the upper limit of Rb/Sr for in-situ Sr isotope determination and reduce the relative standard deviation of results. This improvement of the upper limit of Rb/Sr (<0.33) will expand not only range of microanalysis for silicate minerals, but also bulk Sr isotope determination of volcanic rock combining with rapid fusion technique.

中文翻译：

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LA-MC-ICP-MS改进的硅酸盐样品原位同位素比值测定及其在熔融岩粉中的广泛应用

在原位的固体样品的锶同位素确定具有高空间分辨率和方便，快速的样品制备的优点。但是，由于缺乏从Sr中分离基质元素的柱化学方法，干扰校正（尤其是⁸⁷ Sb上⁸⁷ Rb的等压干扰）成为高精度原位分析的一个大问题。锶同位素分析结果。在这项研究中，我们系统地评估了等压线干扰的影响，并采用了一种改进的策略来校正Rb的等压线干扰。具体而言，作为数据校准的外部标准，将内部硅酸盐标准品（Rb-std）与纯氧化物粉末融合在一起。新标准（Rb-std）显示出极低的Sr（<1 ppm），Yb（<0.09 ppm）和Er（<0.05 ppm）含量，这直接避免了双重电荷离子和等压线的干扰。确定的Rb的质量分馏因子（β RB）。我们的改进方法可以提供比以前的研究更准确的数据，在以前的研究中，质量分数是由具有高Rb（30.07 ppm），Sr（482 ppm），Yb（1.13 ppm）和Er的外部参考材料StHs6 / 80-G计算得出的（1.18 ppm）。然后，将这些β RB从RB-STD通过线性内插施加于未知样品的校正⁸⁷ RB上⁸⁷ Sr的串行国际参照物质的分析结果（BIR-1G，BCR-2G，BHVO-2G，T1- G和ATHO-G）证明我们的改进方法可以提高原位Rb / Sr的上限测定Sr同位素并降低结果的相对标准偏差。Rb / Sr（<0.33）上限的提高不仅将扩大硅酸盐矿物的微观分析范围，而且还将结合快速融合技术对火山岩的本体Sr同位素测定。