Novel application of the X-ray fluorescence method for the determination of FeO content for reference materials characterization.

Novel X-ray fluorescence technique is applied for determination of ferrous iron (FeO) content for reference material characterization in addition (or as alternative) to volumetric method. Approach is based on the dependence of FeKß5 line relative intensity on the iron valence state. A set of 99 reference materials was studied to choose optimal calibration set containing rocks of different composition: ultrabasic, basic, intermediate, and acid igneous rocks, silicate sedimentary and metamorphic rocks. The ratio of FeKß5 and FeKß1,3 lines intensities was chosen as analytical parameter. A set of 40 GeoPT samples was analyzed, and it was shown that the uncertainty of proposed X-ray fluorescence technique is comparable to one of certified volumetric (potassium dichromate titration) technique for the samples with Fe2O3tot content more than 1 wt%. The presence of Sr and Co in usual for rocks content (up to ∼0.23 wt% and ∼200 µg/g respectively) does not affect to the measurement uncertainty. Analytical potential, limitations and features of proposed technique are discussed.

Multielement analysis of continental and lacustrine ferromanganese nodules by WDXRF, TXRF, and ICP-MS methods. Intercomparison study and accuracy assessment.

Specific elemental and mineral composition of lacustrine and continental nodules differ substantially from silicate sedimentary rock, oceanic nodules, and crusts. The examination of this rock type requires study of the applicability of analytical methods to get accurate data on the elemental composition due to the lack of matrix-matched certified reference materials. In this study, multielement analysis of continental and lacustrine ferromanganese nodules was performed using various analytical methods. Samples were prepared as fused glasses and pressed pellets for wavelength-dispersive X-ray fluorescence, suspensions for total reflection X-ray fluorescence, and solutions after fusion for inductively coupled plasma mass spectrometry measurements. An intercomparison test was carried out to study the results using several analytical methods.

Development and validation of a method for multielement analysis of apatite by total-reflection X-ray fluorescence spectrometry.

Apatite group of minerals incorporates a large range of trace metals such as Sr, Y, U, Th, as well as the rare earth elements, that allows obtaining useful information on their genesis and could be used in several applications in geology and geochemistry. In this study, a new method for the multielement analysis of apatite using total-reflection X-ray fluorescence spectrometry (TXRF) was developed. The acid digestion procedure was chosen as an optimal sample preparation with the capability to analyze a low sample amount (~5-10 mg). The validation of the method passed through the combination of procedures: analysis of Durango and Otter Lake well-known apatite samples; using inductively coupled plasma mass spectrometry and wavelength-dispersive X-ray fluorescence spectrometry as reference analytical methods; assessment of the measurement uncertainty. The proposed TXRF method is advantageous in being fast, cheap and simple for the multielement analysis of apatite with high accuracy.

A comparative determination of major components in coal power plant wastes by wavelength dispersive X-ray fluorescence using pellet and fused bead specimens.

The Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, Fe2O3 and S contents were determined in coal power plant waste by X-ray fluorescence using two sample preparation procedures. The differences between XRF results for fused beads and pressed pellets are from 2 to 33%. Grinding of samples to particle size less than 0.050 mm reduces the errors. Pressed pellets method is acceptable for classifying of the waste before recycling; fusion bead method is preferable for highly precise determinations of oxides.

Wavelength dispersive X-ray fluorescence determination of major oxides in bottom and peat sediments for paleoclimatic studies.

The wavelength dispersive X-ray fluorescence method was applied to identify the distribution of major oxides within bottom and peat sediments containing organic matter of up to 70 wt.%. Samples were prepared as glass beads by fusing with lithium metaborate. The accuracy of results was assessed by flame photometry, spectrophotometry, and flame atomic absorption techniques. The proposed technique requires a sample weighing only 110 mg, which allows to analyze each centimeter of core collected at high-mountainous sites with undisturbed environment and eventually achieve uniquely high resolution of paleoclimatic reconstructions of global and regional climatic and environmental changes.