5 research outputs found
Determination of Selenium in Biological Materials by Stable Isotope Dilution Gas Chromatography-Mass Spectrometry
Selenium can be determined quantitatively in biological samples after digestion using nitric acid, orthophosphoric acid, and hydrogen peroxide and the formation of 5-nitropiazselenol. Samples are spiked with enriched 82Se and lsotoplc ratio of 80Se to 82Se is measured by combined gas chromatographymass spectrometry using dual ion monitoring. Precise determination at the parts-per-billion level is possible. The accuracy of the method Is verlfied by using standard reference materials
Recommended from our members
Hanford Immobilized LAW Product Acceptance: Initial Tanks Focus Area Testing Data Package
A matrix of 55 glasses was developed and tested with the aim to identify the impact of glass composition on the long-term corrosion behavior and to develop an acceptable low-activity waste glass composition region. Of the 55 glasses, 45 were designed to systematically vary the glass composition and 10 were selected because large and growing databases on their corrosion characteristics had accumulated. The performance of these 55 glasses in the vapor-phase hydration test (VHT) and product consistency test (PCT) were characterized. VHT's were performed at temperatures between 150?C and 300?C for times up to 280 days; preliminary corrosion rates and type of alteration products were identified. PCTs were performed at 90?C with glass surface area's to solution volumes (S/V) of 2000 m-1 for 7 days and S/V of 20 000 m-1 for 10 h, 100 h, and 1000 h. The corrosion extents by PCT were determined as functions of time from solution composition analyses