Browsing by Author "Donner, E"

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    Geomaterials in the age of megapixel imaging
    (Australian Microscopy and Microanalysis Society, 2016-02-04) Brugger, J; Etschmann, BE; Li, K; Michaut, P; Donner, E; Howard, DL
    Geological samples are extremely diverse and share a tendency for heterogeneity and complexity. This is especially true for ores and for environmental samples, which result from complex processes in dynamic environments. In recent years, a number of tools that enable imaging element distribution in geological samples at 1-50μm-resolution and over cm2 areas have seen rapid development and have become readily available. The application of synchrotron-based X-ray fluorescence mapping has been limited to addressing key questions because of low availability and high cost. However, recent advances in X-ray fluorescence detector technology are bringing new possibilities to petrology. Millisecond dwell times allow collection of thin-section-size maps in hours, and improvement in data analysis produces quantitative elemental maps. The technique can be combined with XANES imaging to provide additional information about element speciation (e.g., As oxidation state). We illustrate applications of M(egapixel)-μXRF for ore petrology (commodities: Au, Pt, U, Cu, Ge, Ti, REE, Nb), coal petrology, and environmental samples. Examples of outcomes include: (i) the distribution of μm-sized Pt-rich grains and Ti-mobility during schistosity formation at the Fifield Pt prospect (Australia); (ii) confirmation of the two-stage Ge-enrichment in the Barrigão deposit (Portugal), with demonstration of the presence of Ge in solid solution in the early chalcopyrite; (iii) enrichment of U during late dissolution-reprecipitation reactions in the Cu-rich ores of the Moonta and Wallaroo IOCG deposits (Australia); (iv) history of REE-Ti-Nb-(As) mobility during amphibolite to greenschist facies metamorphism in the Binntal Valley, Switzerland; (v) contrasting distribution of As, Ge and W in Ge-rich coals across the Globe; and (vi) evolution of the distribution and speciation of Cu upon aging of biosolids.
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    Investigating the foliar uptake of zinc from conventional and nano-formulations: a methodological study
    (CSIRO Publishing, 2019-06-06) Read, TL; Doolette, CL; Cresswell, T; Howell, NR; Aughterson, RD; Karatchevtseva, I; Donner, E; Kopittke, PM; Schjoerring, JK; Lombi, E
    Zinc (Zn) deficiency affects half of the world’s arable soil and one-third of the world’s human population. Application of Zn foliar fertilisers to cereal crops can be an effective way to increase grain Zn content; however, commonly used formulations can scorch the leaf (e.g. soluble Zn salts) or are prohibitively expensive (e.g. chelated Zn, ZnEDTA). Zinc oxide nanoparticles (ZnO-NPs) may offer an efficient and cost-effective alternative, but little is known regarding the mechanisms of Zn uptake and translocation within the plant. Foliar-applied Zn is analytically challenging to detect, locate and quantify, as it is omnipresent. Furthermore, any single analytical technique does not have the detection limit or spatial resolution required. In this study, the uptake and mobility of foliar-applied ZnEDTA, ZnO-NPs and ZnO microparticles (ZnO-MPs) to wheat (Triticum aestivum L.) were investigated using inductively coupled plasma mass spectroscopy (ICP-MS), synchrotron-based X-ray fluorescence microscopy (XFM) and radiotracing techniques using 65Zn-labelled formulations. The three techniques were compared to highlight limitations and advantages of each. We also report, for the first time, a novel time-resolved in vivo autoradiography imaging technique that can be used to visualise 65Zn in live plants treated with foliar applications of 65ZnO-NPs and MPs. The images were supplemented by gamma spectroscopy analysis for quantification. The results of this study provide important insights into the analytical challenges faced when investigating foliar-applied Zn nanofertilisers in plants. Potential solutions using nuclear techniques are also discussed, which in turn may ultimately lead to the development of more efficient foliar fertilisers. © CSIRO 2019