The insufficient spectral resolution of the energy-dispersive total-reflection X-ray fluorescence (TXRF) complicates the U and Th Lα lines using for the quantitative determination of low concentrations of these elements in natural solid samples.

The quality of total reflection X-ray fluorescence (TXRF) analysis data for S, Ni, and Cu in copper nickel sulfide ores has been assessed in the framework of an interlaboratory comparison program, with allowance for requirements that should be met by techniques for determination of the chemical composition of mineral raw materials. Certified techniques for analysis of mineral raw materials by this method are not available, and the results obtained in the interlaboratory comparison program were used to assess and improve TXRF measurement accuracy. Ore samples were prepared in the form of suspensions using wet grinding. The analytical signal used was the intensity ratio of characteristic lines of the elements to be determined and a Ga internal standard. To construct calibration curves, we used reference samples analyzed by certified techniques: Cu and Ni were determined by atomic absorption, and S by gravimetry. The quality of analytical data was assessed using the Z-criterion. The random measurement error did not exceed 5% relative. The relative discrepancies between the TXRF results and interlaboratory comparison test results were within 10%. The described technique can be used for rapid analysis of copper nickel sulfide ore samples.

This study evaluates wavelength-dispersive X-ray fluorescence (WDXRF) for the quantification of iron and other major elements in archeological ochre, employing a borate-flux fusion technique adapted for small sample quantities. Cross-sectional microXRF mapping of glass samples fused from iron ore reference materials confirmed high compositional homogeneity for Fe, Si, K, and Ca across a broad concentration range. WDXRF calibration curves, derived from twenty certified reference materials of iron ores, facilitated the quantification of Mg, Al, Si, P, Ca, Ti, Mn, and Fe in samples with an iron content spanning 25–66 wt.%. The approach was validated via WDXRF and flame atomic absorption spectrometry (FAAS) analysis of seven archaeological ochre specimens from the Paleolithic site Kamennaya Balka II, covering the primary iron-bearing phases of goethite, jarosite, hematite, and magnetite. The agreement between WDXRF and FAAS samples confirms the accuracy of iron determination, irrespective of the iron mineral phase.