Secondary ion mass spectrometry of lithium content and isotope ratios in carbon matrices.
Secondary ion mass spectrometry of lithium content and isotope ratios in carbon matrices.
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碳基质中锂含量和同位素比的二次离子质谱法。
DOI：
10.1111/ggr.12415
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发表时间：
2022
影响因子：
3.8
通讯作者：
Williams. L.B.
中科院分区：
文献类型：
--
作者：
Teichert, Z.;Bose, M.;Williams, P.;Hervig., R.L.;Williams. L.B.
二次离子质谱技术用于研究基质组成有空间差异的有机样品中的微量元素。本研究旨在建立干酪根中锂含量和锂同位素测量的校准方法。已知浓度的锂离子（6Li和7li）被植入有机聚合物中，其H/C和O/C比值范围与干酪根相似，还有玻璃碳（SPI glass‐22）和硅酸盐玻璃（NIST SRM 612）。结果表明，在5 kV二次离子加速电压下，碳质样品的锂含量校正因子（K*）是相似的。在9 kV二次离子加速电压下，K*因子与样品O含量呈负相关，在0 ~ 15氧原子%之间变化~ 30%。因此，为了避免与O含量相关的矩阵效应，基于7li +/12C+比值定量Li含量时，使用5kv二次离子加速电压是最好的。在这些分析条件下，测得Li ppm（原子）=（132（±8）×7Li+/12C+） ×12C原子分数的样品。SPI glass‐22和NIST SRM 612的锂同位素比测量在不确定度内；有机聚合物样品的δ7Li值比NIST SRM 612高10‰。
Secondary ion mass spectrometry techniques are used to study trace elements in organic samples where matrix compositions vary spatially. This study was conducted to develop calibrations for lithium content and lithium isotope measurements in kerogen. Known concentrations of Li ions (6Li and7Li) were implanted into organic polymers, with a range of H/C and O/C ratios similar to kerogen, along with glassy carbon (SPI Glas‐22) and silicate glass (NIST SRM 612). Results show that Li content calibration factors (K*) are similar for carbonaceous samples when analysed using a 5 kV secondary ion accelerating voltage. Using a 9 kV secondary ion accelerating voltage,K* factors are negatively correlated with the sample O content, changing ~ 30% between 0 and 15 oxygen atomic %. Thus, to avoid the matrix effect related to O content, using a 5 kV secondary ion accelerating voltage is best for quantification of Li contents based on7Li+/12C+ratios. Under these analytical conditions, Li ppm (atomic) = (132 (± 8) ×7Li+/12C+) ×12C atom fraction of the sample measured. Lithium isotope ratio measurements of SPI Glas‐22 and NIST SRM 612 are within uncertainty; however, the organic polymer samples as a group show a 10‰ higher δ7Li than NIST SRM 612.