Two new reference materials based on tobacco leaves: certification for over a dozen of toxic and essential elements.

The preparation, certification, and characterization of two new biological certified reference materials for inorganic trace analysis have been presented. They are based on two different varieties of tobacco leaves, namely, Oriental Basma Tobacco Leaves (INCT-OBTL-5), grown in Greece, and Polish Virginia Tobacco Leaves (INCT-PVTL-6), grown in Poland. Certification of the materials was based on the statistical evaluation of results obtained in a worldwide interlaboratory comparison, in which 87 laboratories from 18 countries participated, providing 2568 laboratory averages on nearly 80 elements. It was possible to establish the certified values of concentration for many elements in the new materials, that is, 37 in INCT-OBTL-5 and 36 in INCT-PVTL-6, including several toxic ones like As, Cd, Hg, Pb, and so forth. The share and the role of instrumental analytical techniques used in the process of certification of the new CRMs are discussed.

Novel radiochemical separation of arsenic from selenium for 72Se/72As generator.

A new radiochemical separation scheme based on extraction chromatography has been proposed for isolation of arsenic from selenium. The distribution coefficients of As and Se on prepared sorbents: (selected aromatic o-diamines supported on polystyrene adsorbents) were determined in order to find the best condition for separation of both the elements. Batch experiments were verified by column studies. This work, together with earlier results from this Laboratory, enabled to elaborate a new separation scheme for selective and quantitative separation of arsenic from selenium. Proposed approach insures high selectivity and radionuclide purity of separated arsenic fraction; it is also characterized by high elution efficiency (>95%) using small volume (2 mL) of 0.9% NaCl with very low breakthrough (<0.01%) of selenium.