NanoSIMS as a tool for characterizing soil model compounds and organomineral associations in artificial soils
NanoSIMS as a tool for characterizing soil model compounds and organomineral associations in artificial soils
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DOI：
10.1007/s11368-011-0386-8
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发表时间：
2012-01-01
影响因子：
3.6
通讯作者：
Koegel-Knabner, Ingrid
中科院分区：
文献类型：
--
作者：
Heister, Katja;Hoeschen, Carmen;Koegel-Knabner, Ingrid
纳米尺度二次离子质谱（NanoSIMS）是土壤科学中一种新的和有前途的技术，因为它使我们能够在亚微米尺度上以高灵敏度探索固体样品的元素和同位素组成。在这项研究中，我们证明了它是可能的区分土壤的主要组成部分，为此，我们采用了培养的土壤成分（粘土矿物，氧化铁，有机质，石英）的混合物，所谓的人工土壤样品。样品制备的粒度和密度分数的土壤中的各种成分，并与反射光和电子显微镜结合能量色散X射线光谱NanoSIMS分析之前，我们的研究结果表明，我们能够显示各种成分的亚微米排列，并区分木炭和土壤有机质。有机材料的矿物表面的附着主要发生在片状结构的粘土矿物，而只有很少的吸附均匀分布的有机材料上的铁氧化物发生。虽然有几个原因可以想象为什么我们没有检测到更多的有机物吸附到铁氧化物，这很可能是由中性pH值的土壤，阻碍吸附到可变电荷的表面网站的铁氧化物。因此，NanoSIMS使分析亚微米过程在土壤科学相关的研究。然而，土壤颗粒的非常不均匀的基质导致不同的电离率将使得定量分析的尝试变得困难，这也是由于缺乏代表这些复杂基质的合适标准的可用性。
Secondary ion mass spectrometry at the nanoscale (NanoSIMS) is a new and promising technique in soil science, as it allows us to explore the elemental and isotopic composition of a solid sample with high sensitivity at a submicron scale. In this study, we demonstrate that it is possible to differentiate the major components of soils by this technique.For this purpose, we employed samples from incubated mixtures of soil components of known composition (clay minerals, Fe oxide, organic material, and quartz), so-called artificial soils. Samples were prepared from particle size and density fractions of soils of various compositions and investigated with reflected light and electron microscopy in combination with energy dispersive X-ray spectroscopy prior to NanoSIMS analysis.Our results show that we were able to show the submicron arrangement of the various components and to differentiate between charcoal and soil organic matter. Attachment of organic material to mineral surfaces was predominantly found to occur in patchy structures on the clay minerals, whereas only little sorption of homogeneously distributed organic material onto Fe oxides occurred. Although there are several reasons conceivable why we did not detect more sorption of organic matter to Fe oxides, it is likely that this is caused by the neutral pH of the soils, hampering sorption to the variable-charged surface sites of the Fe oxide.Consequently, NanoSIMS enables the analysis of submicron processes in soil science-related research. However, the very heterogeneous matrix of soil particles leading to various ionization rates will make attempts for a quantitative analysis difficult, which is also due to a lack in the availability of suitable standards representing these complex matrices.