An interlaboratory study of TEX86 and BIT analysis using high‐performance liquid chromatography–mass spectrometry
An interlaboratory study of TEX86 and BIT analysis using high‐performance liquid chromatography–mass spectrometry
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DOI：
10.1029/2008gc002221
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发表时间：
2009-03
期刊：
影响因子：
3.7
通讯作者：
Stefan Schouten;E. Hopmans;J. V. D. Meer;A. Mets;T. Bianchi;A. Diefendorf;C. Huguet;A. Ingalls;A. Nederbragt
中科院分区：
文献类型：
--
作者：
Stefan Schouten;E. Hopmans;J. V. D. Meer;A. Mets;T. Bianchi;A. Diefendorf;C. Huguet;A. Ingalls;A. Nederbragt
最近，基于甘油二烷基甘油四醚（GDGT）的分布提出了两个新的替代物，即，用TEX 86代用指标重建海洋表面温度，用BIT指数重建土壤有机质输入海洋。在这项研究中，15个实验室参加了一个循环研究的两个沉积物提取物与一系列的TEX 86和BIT值，以测试分析的重现性和重复性，在分析这些代理。对于TEX 86，两种沉淀物浸提液的重复性（表明实验室内变化）为0.028和0.017，或转换为温度时为±1-2°C。TEX 86测量的再现性（表明实验室间差异）显著较高，即，0.050和0.067或±3-4°C（转换为温度时）。后者的值高于Mg/Ca和U37 k ′古温度计的循环研究中获得的值，这表明需要主要改善实验室之间的兼容性。大量的土壤有机质输入的沉积物的BIT测量的重复性相对较小，0.029，但再现性大，0.410。这一巨大差异不能归因于所使用的具体设备或特定的数据处理方法。我们认为，这可能是由于BIT指数中使用的GDGT分子量差异较大所致，即，crenarchaeol与分支GDGT。潜在地，这种差异在所使用的不同质谱仪中引起可变响应。需要使用真实标准进行校准，以建立进行BIT测量的实验室之间的兼容性。
Recently, two new proxies based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) were proposed, i.e., the TEX86 proxy for sea surface temperature reconstructions and the BIT index for reconstructing soil organic matter input to the ocean. In this study, fifteen laboratories participated in a round robin study of two sediment extracts with a range of TEX86 and BIT values to test the analytical reproducibility and repeatability in analyzing these proxies. For TEX86 the repeatability, indicating intralaboratory variation, was 0.028 and 0.017 for the two sediment extracts or ±1–2°C when translated to temperature. The reproducibility, indicating among‐laboratory variation, of TEX86 measurements was substantially higher, i.e., 0.050 and 0.067 or ±3–4°C when translated to temperature. The latter values are higher than those obtained in round robin studies of Mg/Ca and U37k′ paleothermometers, suggesting the need to primarily improve compatibility between labs. The repeatability of BIT measurements for the sediment with substantial amounts of soil organic matter input was relatively small, 0.029, but reproducibility was large, 0.410. This large variance could not be attributed to specific equipment used or a particular data treatment. We suggest that this may be caused by the large difference in the molecular weight in the GDGTs used in the BIT index, i.e., crenarchaeol versus the branched GDGTs. Potentially, this difference gives rise to variable responses in the different mass spectrometers used. Calibration using authentic standards is needed to establish compatibility between labs performing BIT measurements.