The material was prepared from soya bean grown in India, not genetically modified. After milling, the material was sieved through the 150 mm nylon sieves and stored in a polyethylene (PE) bag. Approximately 50 kg of sieved soya bean flour was collected. Examination by optical microscopy revealed that Martin’s diameter of over 90% of particles was below 50 mm. The whole lot of soya bean flour was then homogenized by mixing for 20 hours in a 110 dm3 PE drum rotated in three directions. Preliminary homogeneity testing by XRF method and final checking of homogeneity by NAA after distribution of the material into containers revealed, that it is sufficiently homogeneous at least for a sample size ³ 100 mg. In order to assure the long-term stability, all containers with INCT-SBF-4 were sterilized by electron beam radiation. Long-term stability was checked by analyzing concentrations of selected elements in the material stored in the air-conditioned room at 20°C. Short-term stability was examined by the determination of concentrations of the selected elements in the bottle stored in the CO2 incubator at 37°C. The shelf life of INCT-SBF-4 has been established to be 31 December 2015. The material was certified on the basis of a worldwide interlaboratory comparison, in which 92 laboratories from 19 countries. Analytical uncertainties and stability uncertainties were quantified to arrive at combined uncertainties of the certified values. Recommended values are assigned for:
Al, B, Ba, Br, Ca, Cl, Co, Cs, Cu, Fe, K, La, Mg, Mn, Mo, Ni, P, Rb, S, Sr, Sc, Th, Zn.;
Information values are assigned for:
Ca, Cd, Hg, Na, Pb, Sc, Sm, Ti, V;
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