The certification of the mass fraction of carbon in cementite grains in a Fe-C matrix: IRMM-471

The report describes the production and certification of IRMM-471, a reference material certified for the carbon mass fraction of its cementite (Fe3C) grains. The Fe3C grains are dispersed within an iron pearlite matrix and present an average grain diameter between 20 µm and 50 μm. IRMM-471 has been produced and certified in order to be used as calibrant in electron probe micro-analyser (EPMA) for carbon determination in iron and steel products.JRC.D.2-Standards for Innovation and sustainable Developmen

Optimisation of asymmetric flow field-flow fractionation for the characterisation of polydisperse TiO2 with applications in food and feed

In the present work an optimisation process for the characterisation of a polydisperse TiO2 is presented. As a first step probe ultrasonication was optimised in which the amplitude and time were the selected variables in order to disperse, i.e. to break up agglomerates and/or aggregates of the material. The results showed that high amplitudes favoured a better dispersion while time had no impact. In a next step the important factors of Assymmetric Flow Field Flow Fraction (AF4), namely cross flow (CF), detector flow (DF), cross flow rate or exponential decay of the cross flow (CFexp) and focus time (Ft) were studied by experimental design. Firstly a full factorial design was employed to establish the statistically significant factors (p-level < 0.05). Then, the information obtained from the full factorial design was utilised to apply a central composite design, in order to get the following optimum conditions of the system: CF, 1.6 mL/min; DF, 0.4 mL/min; Ft, 5 min and CFexp 0.6. Once the optimum conditions were obtained the stability of the dispersed sample was measured during 24 h by analysing 10 replicates with AF4, in order to assess the performance of the optimised dispersion protocol. Finally, the effect of the temperature on the particle size distribution, recovery and retention time was studied in the range of 25-45 °C, to check whether the method was robust against the variation of the temperature.JRC.F.5-Food and Feed Complianc

Investigation of Uranium Isotopic Signatures in Real-Life Particles from a Nuclear Facility by Thermal Ionization Mass Spectrometry

An improved method was recently developed for the isotopic analysis of single-reference uranium oxide particles for nuclear safeguards. This method is a combination of analytical tools including in situ SEM micromanipulation, filament carburization and multiple ion counting (MIC) detection, which is found to improve sensitivity for thermal ionization mass spectrometry (TIMS) isotope ratio analysis. The question was raised whether this method could be applied for the detection of nuclear signatures in real-life particles with unknown isotopic composition. Therefore, environmental dust was collected in different locations within a nuclear facility. The screening of the samples to find the uranium particles of interest was performed using a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray (EDX) detector. The comparison of the measurement results to reference data evaluated by international safeguards authorities was of key importance for data interpretation. For the majority of investigated particles, detection of uranium isotopic signatures provided information on current and past nuclear feed operations that compared well with facility declarations.JRC.DG.D.2-Reference material