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X-ray fluorescence laboratory

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X-ray fluorescence laboratory

The laboratory houses a 2010 PANalytical Axios sequential X-ray fluorescence spectrometer with 4kW Rh-anode X-ray tube and a wide range of diffraction crystals. There is also a preparation laboratory for pellet-making and fusions. It is primarily focussed on deriving high-accuracy high-reproducibility major and trace element analyses on igneous, metamorphic and sedimentary rocks, of silicate, carbonate, phosphate or sulphate bulk composition. However, a wide variety of other materials may be analysed qualitatively, semi-quantitatively, or quantitatively if standards are available or provided by the user.

Elements analysed depend on the application and sample type. For example, our standard analyses for rock samples include:

Major elements (on fused glass discs using ~0.7g sample): SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O, TiO2, MnO, P2O5, Cr2O3, SO3, Cl, F (note that S and Cl may be volatilized during fusion). Fused discs are prepared using ignited sample powders (giving LOI) mixed with ignited Spectroflux 105 in a constant 1:5 ratio. Matrix corrections are very small.

Trace elements (on ~10g pressed pellets, requires major element analysis as well): Mo, Nb, Zr, Y, Sr, U, Rb, Th, Pb, As, Br, Ga, Zn, W, Ta, Hf, Cu, Ni, Yb, Co, Sm, Cr, Ce, Nd, V, La, Ba, Cs, Sc, Sn, Cl, S, F. In addition, Fe2O3, CaO and TiO2are analysed as cross-checks to the major element data. Trace element data are calculated using matrix corrections based on the major element data.

We also provide scan-based semi-quantitative analysis of unknown samples using the PANalytical application Omnian, and trace element analysis of samples with no major element data using the PANalytical application ProTrace.

The laboratory is available for in-house, collaborative and commercial use, and costs depend on the type of analysis, the degree to which the user wants to be involved, and whether the work is collaborative or commercial.

Typical reproducibility is available at
https://docs.google.com/spreadsheets
Typical calibration graphs are at:
https://docs.google.com/presentation
and comparisons between XRF and isotope dilution data for several elements are at:
https://docs.google.com/presentation

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