Automation of boron chromatographic purification for d11 B analysis of coral aragonite.
Automation of boron chromatographic purification for d11 B analysis of coral aragonite.
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用于珊瑚霰石 d11 B 分析的硼色谱纯化自动化。
DOI：
10.1002/rcm.8762
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发表时间：
2020
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影响因子：
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通讯作者：
De La Vega E
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作者：
De La Vega E
为了检测过去pH的微小变化，珊瑚碳酸盐的硼同位素比值（以δ11B值表示）需要既精确又准确（2sd <<1‰）。通过多收集器电感耦合等离子体质谱（MC - ICPMS）测量硼需要在分析前仔细纯化硼，这是耗时的，并且需要专业培训。在这里，我们使用prepFAST‐MC方法，可以从caco3基质中自动提取B（高达25 ng负载）。方法采用~25 μL Amberlite IRA743树脂柱，采用预fast - MC自动纯化系统。硼同位素测量用MC - ICPMS进行。测试了基质负载、样品上样速度和空白污染对纯化过程的影响。优化后的方案在各种标准和文石珊瑚样本上进行了测试。结果该方法的空白贡献为~ 60pg，考虑到我们的样本量（<0.2%样本量），空白贡献可以忽略不计。通过向NIST SRM 951中添加高达1.6 mg溶解的低B型碳酸钙，证明了基质去除的效率，并且对δ11B值的准确性没有影响。采用预fast‐MC系统处理的日本地质调查局孔隙基准物质JCp‐1、硼酸标准品NIST SRM 951和海水的δ11B值均在文献误差范围内(δ11BJCp‐1= 24.31±0.20‰（2sd,n= 20）；δ11 bnist 951 =−0.02±0.15‰(2 sd, n = 13)和11 bseawaterδ= 39.50±0.06‰(2 sd, n = 2))。使用prepFAST‐MC系统纯化的coralSiderastrea sidereere纯化的结果显示，与手动离子交换协议的平均偏移量为Δδ11B = 0.01±0.28‰（2sd,n= 12）。研究表明，pre - fast‐MC方法能够在不需要分馏法、基质去除效率高、空白贡献可忽略的情况下，对一系列材料产生准确、可重复的δ11B值。
RationaleTo detect the small changes in past pH,the boron isotope ratio of coral carbonates, expressed as the δ11B value, needs to be both precise and accurate (2sd <<1‰). Boron measurements by Multi‐Collector Inductively Coupled Plasma Mass Spectrometry (MC‐ICPMS) require the boron to be carefully purified before analysis, which is time consuming, and requires specialist training. Here, we use the prepFAST‐MC method that enables the automatic extraction of B (up to 25 ng load) from a CaCO3matrix.MethodsSamples were purified using the prepFAST‐MC automated system with a ~25‐μL column of Amberlite IRA743 resin. Boron isotope measurements were performed by MC‐ICPMS. The effects of matrix load, speed of sample loading onto the column, and blank contamination were tested to evaluate the effects on the purification process. The optimised protocol was tested on various standards and samples of aragonite corals.ResultsThe blank contribution for the approach is ~60 pg and is negligible given our sample size (<0.2% sample size). Efficiency of matrix removal is demonstrated with the addition of up to 1.6 mg of dissolved low‐B calcium carbonate to NIST SRM 951 with no impact on the accuracy of δ11B values. The Japanese Geological Survey Porites reference material JCp‐1, boric acid standard NIST SRM 951, and seawater, all processed on the prepFAST‐MC system, give δ11B values within error of literature values (δ11BJCp‐1= 24.31 ± 0.20‰ (2sd,n= 20); δ11BNIST 951= −0.02 ± 0.15‰ (2sd,n= 13) and δ11BSeawater= 39.50 ± 0.06‰ (2sd,n= 2)). Results obtained from the coralSiderastrea sidereapurified with the prepFAST‐MC system show an average offset from the manual ion‐exchange protocols of Δδ11B = 0.01 ± 0.28‰ (2sd,n= 12).ConclusionsOur study demonstrates the capacity of the prepFAST‐MC method to generate accurate and reproducible δ11B values for a range of materials, without fractionation, with efficient matrix removal and with negligible blank contribution.