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TRU resin can be used to rapidly and selectively extract Tc(VII) and Re(VII). The retention capacity curves of Tc(VII) and Re(VII) for HNO3, HCl, H2SO4 and H3PO4 solutions were studied and prepared. Tc(VII) and Re(VII) were simultaneously extracted in 2 M H2SO4 and 1.5 M H3PO4 and were effectively separated from Mo(VI) and Ru(III). Tc(VII) and Re(VII) remained strongly bonded to the resin even after washing using a large volume of 2 M H2SO4 at a relatively high flow rate. Also, they were both completely eluted from the resin using 15 mL of near boiling water, an eluent directly compatible for ICP-MS instrument measurements. [ABSTRACT FROM AUTHOR]

While production of engineered carbon nanotubes (CNTs) has escalated in recent years, knowledge of risk associated with exposure to these materials remains unclear. We report on the cytotoxicity of four CNT variants in human lung epithelial cells (A549) and murine macrophages (J774). Morphology, metal content, aggregation/agglomeration state, pore volume, surface area and modifications were determined for the pristine and oxidized single-walled (SW) and multi-walled (MW) CNTs. Cytotoxicity was evaluated by cellular ATP content, BrdU incorporation, lactate dehydrogenase (LDH) release, and CellTiter-Blue (CTB) reduction assays. All CNTs were more cytotoxic than respirable TiO2 and SiO2 reference particles. Oxidation of CNTs removed most metallic impurities but introduced surface polar functionalities. Although slopes of fold changes for cytotoxicity endpoints were steeper with J774 compared to A549 cells, CNT cytotoxicity ranking in both cell types was assay-dependent. Based on CTB reduction and BrdU incorporation, the cytotoxicity of the polar oxidized CNTs was higher compared to the pristine CNTs. In contrast, pristine CNTs were more cytotoxic than oxidized CNTs when assessed for cellular ATP and LDH. Correlation analyses between CNTs' physico-chemical properties and average relative potency revealed the impact of metal content and surface area on the potency values estimated using ATP and LDH assays, while surface polarity affected the potency values estimated from CTB and BrdU assays. We show that in order to reliably estimate the risk posed by these materials, in vitro toxicity assessment of CNTs should be conducted with well characterized materials, in multiple cellular models using several cytotoxicity assays that report on distinct cellular processes. [ABSTRACT FROM AUTHOR]