Novel Sample Preparation Technique To Improve Spectromicroscopic Analyses of Micrometer-Sized Particles
Novel Sample Preparation Technique To Improve Spectromicroscopic Analyses of Micrometer-Sized Particles
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DOI：
10.1021/acs.est.5b01636
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发表时间：
2015-08-18
影响因子：
11.4
通讯作者：
Koegel-Knabner, Ingrid
中科院分区：
文献类型：
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作者：
Hoeschen, Carmen;Hoeschen, Till;Koegel-Knabner, Ingrid
土壤和沉积物中生物地球化学界面发生的微观过程对更大规模的现象具有根本性影响。为了获得生物地球化学界面研究所需的有机矿物关联，通常将大块样品分成微聚集体或微米尺寸的单个颗粒。这种细粒矿物颗粒通常通过将其沉积在载体上来制备用于纳米级二次离子质谱（NanoSIMS）研究。这会引入地形差异，从而强烈影响局部溅射效率。嵌入树脂中会产生不需要的 C 杂质。我们提出了一种制备微米级原生土壤颗粒抛光横截面的新方法，克服了地形和碳污染的问题。颗粒上涂有标记层、嵌入并抛光良好。 NanoSIMS 数据的解释由聚焦离子束制备的横截面的能量色散 X 射线光谱仪辅助。在横截面中，原生土壤颗粒上的有机组合变得可见。这种新颖的方法显着提高了颗粒矿物样品的 NanoSIMS 测量质量，从而能够更好地表征土壤生物地球化学界面。此外，这种样品制备技术还可以改善其他（光谱）显微技术的结果。
Microscale processes occurring at biogeochemical interfaces in soils and sediments have fundamental impacts on phenomena at larger scales. To obtain the organo-mineral associations necessary for the study of biogeochemical interfaces, bulk samples are usually fractionated into microaggregates or micrometer-sized single particles. Such fine-grained mineral particles are often prepared for nanoscale secondary ion mass spectroscopy (NanoSIMS) investigations by depositing them on a carrier. This introduces topographic differences, which can strongly affect local sputtering efficiencies. Embedding in resin causes undesired C impurities. We present a novel method for preparing polished cross-sections of micrometer-sized primary soil particles that overcomes the problems of topography and C contamination. The particles are coated with a marker layer, embedded, and well-polished. The interpretation of NanoSIMS data is assisted by energy-dispersive X-ray spectroscopy on crosssections prepared by a focused ion beam. In the cross-sections, organic assemblages on the primary soil particles become visible. This novel method significantly improves the quality of NanoSIMS measurements on grainy mineral samples, enabling better characterization of soil biogeochemical interfaces. In addition, this sample preparation technique may also improve results from other (spectro-) microscopic techniques.