Impact of sample preparation methods for characterizing the geochemistry of soils and sediments by portable X-ray fluorescence
Impact of sample preparation methods for characterizing the geochemistry of soils and sediments by portable X-ray fluorescence
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DOI：
10.1002/saj2.20004
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发表时间：
2020-01-01
影响因子：
2.9
通讯作者：
Bettis, E. Arthur, III
中科院分区：
文献类型：
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作者：
Goff, Kathleen;Schaetzl, Randall J.;Bettis, E. Arthur, III
我们考察了三种不同的样品制备方法对手持便携式X射线荧光(PXRF)光谱仪获得的大量土壤地球化学数据的影响。我们从地表的土芯中提取数据，向下进入未改变的黄土，然后进入爱荷华州东部一个地点的埋藏土壤。(I)直接从野外潮湿的土壤岩心扫描样品；(Ii)干燥、研磨并松散地聚集在塑料杯中；以及(Iii)作为压粉颗粒。使用这些方法得到的数据与从标准台式X射线荧光(XRF)装置获得的数据进行了比较。一般来说，结果表明，压制粉末颗粒的数据通常与台式XRF数据具有最好的相关性，尽管结果有时是特定于元素或化合物的。氧化钙、氧化铁和氧化钾通常在pXRF和XRF报告的值之间提供了最强的相关性；二氧化硅数据更有问题。现场潮湿的pXRF扫描通常低估了元素浓度，但在应用pXRF衍生的校准标准后，pXRF和台式XRF测量之间的相关性得到了极大改善。总而言之，尽管pXRF提供的元素/化合物数据与台式XRF数据有很大关系，但通过适当的样品制备(即干燥、研磨、压制)以及通常通过对照已知标准校准pXRF数据，结果会得到改进。
We examined the impact of three different sample preparation methods on bulk soil geochemistry data obtained from a hand-held, portable X-ray fluorescence (pXRF) spectrometer. We generated data from a soil core recovered from the surface, downward into unaltered loess, and into a buried soil at a site in eastern Iowa. Samples were scanned (i) directly from field-moist soil cores; (ii) after drying, grinding, and being loosely massed in plastic cups; and (iii) as pressed-powder pellets. Data derived using these methods were compared with data obtained from a standard benchtop X-ray fluorescence (XRF) unit. Generally, the results indicated that data from pressed powder pellets often provide the best correlation to benchtop XRF data, although the results were sometimes element or compound specific. Calcium oxide, Fe2O3, and K2O generally provided the strongest correlations between pXRF- and XRF-reported values; SiO2 data were more problematic. Field-moist pXRF scans generally underestimated element concentrations, but the correlations between pXRF and benchtop XRF measurements were greatly improved after applying pXRF-derived calibration standards. In summary, although element/compound data provided by pXRF showed significant relationships to benchtop XRF data, the results are improved with proper sample preparation (i.e., drying, grinding, pressing) and usually by calibrating the pXRF data against known standards.