A method for precise analysis of trace element/calcium ratios in carbonate samples using quadrupole inductively coupled plasma mass spectrometry
A method for precise analysis of trace element/calcium ratios in carbonate samples using quadrupole inductively coupled plasma mass spectrometry
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使用四极杆电感耦合等离子体质谱精确分析碳酸盐样品中痕量元素/钙比的方法
DOI：
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发表时间：
2006
期刊：
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通讯作者：
R. Rickaby
中科院分区：
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作者：
D. Harding;J. W. Arden;R. Rickaby
开发了一种改进的方法，使用四极电感耦合等离子体质谱仪（Q-ICP-MS）分析碳酸盐样品中的多种微量元素与钙的比例。通过操作仪器将每个微量金属测量值与钙测量值进行交叉，可以克服缓解短期漂移的问题，而通过将每个样品分析与典型有孔虫组成的外部基质匹配标准品进行交叉，可以校正长期漂移。我们的方法是最佳的测量比率，Sr/Ca，Mg/Ca，Zn/Ca，Cd/Ca，Ba/Ca，Mn/Ca，和U/Ca，从一个单一的碳酸盐样品，但可以适应包括一系列的替代比例。评价表明该方法非常精确。3种痕量金属与钙的比值的RSD（1σ）小于1，我们实现了与扇形场ICP-MS仪器相当的精密度，并优于使用Q-ICP-MS仪器的先前方法。基于使用100 mg/L Ca标准品在9个月内进行的5个批次中的96个样品分析，每个比值的精密度（RSD）分别为U/Ca 2.2%、Cd/Ca 1.7%、Zn/Ca 1.9%、Ba/Ca 1.1%、Mn/Ca 0.7%、Sr/Ca和Mg/Ca 0.7%和0.6%。通过比较标准比与ICP-AES仪器获得的标准比，并通过比较来自北大西洋的NEAP 4 B材料的样品分析与使用热电离质谱法（TIMS）和火焰原子吸收光谱法（FAAS）测量的数据，证实了该方法的准确性。
An improved method has been developed using a quadrupole inductively coupled plasma mass spectrometer (Q‐ICP‐MS) to analyze carbonate samples for multiple trace element to calcium ratios. Problems alleviating shorter‐term drift have been overcome by manipulating the instrument to bracket each trace metal measurement with a calcium measurement, while longer‐term drift is corrected by bracketing each sample analysis with external matrix‐matched standards, of typical foram composition. Our method is optimized for measuring the ratios, Sr/Ca, Mg/Ca, Zn/Ca, Cd/Ca, Ba/Ca, Mn/Ca, and U/Ca, from a single carbonate sample but could be adapted to include a range of alternative ratios. Evaluation has shown the method to be extremely precise. At less than 1 RSD (1σ) for 3 trace metal to calcium ratios, we have achieved comparable precision to a sector field ICP‐MS instrument and an advance over previous methods using the Q‐ICP‐MS instrument. Precision (RSD) for each ratio, based on 96 sample analyses in 5 batches made over a period of 9 months using a 100 mg/L Ca standard, is 2.2% for U/Ca, 1.7% for Cd/Ca, 1.9% for Zn/Ca, 1.1% for Ba/Ca, 0.7% for Mn/Ca, and 0.7% and 0.6% for Sr/Ca and Mg/Ca, respectively. Accuracy of the method is confirmed by comparing standard ratios with those obtained from an ICP‐AES instrument and by comparing sample analyses of NEAP4B material from the North Atlantic with data measured using thermal ionization mass spectrometry (TIMS) and flame atomic absorption spectroscopy (FAAS).