Different Concentrations Of Se Research Articles

Optimisation of flow-injection-hydride generation inductively coupled plasma spectrometric determination of selenium in electrolytic manganese

Flow-injection-hydride generation procedure for Se in electrolytic manganese was optimized by means of the experimental design approach. Instrumental variables like power supplied ( P), sample ( F) and argon ( G) flow rates together with chemical variables like NaBH 4 and HCl concentrations were studied. In case of the chemical variables, it was concluded that sodium tetrahydridoborate concentrations higher than 1.0% extinguished the plasma while HCl concentration should always be higher than 0.6 mol dm −3. The analysis of effects suggested that all the instrumental variables are significant factors, and the optimum conditions were P = 1550 W, F = 4.75 mL min −1 and G = 0.6 mL min −1. The influence of Mn was specially studied and it was concluded that the interferences were negligible if Mn is below 2.0 g L −1. In the same sense, the interferences of antimony(III), arsenic(V) and mercury(II) were also considered negligible. Finally, a detection limit of 0.0005% (w/w) was obtained (a repeatability R.S.D. <2.0% for all Se concentrations tried). Some manganese samples were also spiked with different concentrations of Se(IV) and the results demonstrated to be in good statistical agreement with expected values.

Selenium Assimilation and Differential Response to Elevated Sulfate and Chloride Salt Concentrations in Two Saltgrass Ecotypes

A comparative study of selenium (Se) assimilation under the influence of sulfate and chloride salt salinity was conducted on two saltgrass ecotypes. The inland saltgrass grows successfully on the soil contaminated with elevated Se concentrations at Kesterson, Merced County, California. The coastal saltgrass colonizes a tidal salt marsh in Bodega Bay on the coast of California. The saltgrass samples were grown in sand culture and irrigated with quarter concentration of modified Hoagland solution supplemented with different concentrations of Se with or without sulfate or chloride salt. The Bodega Bay plants exhibited greater tolerance to both the sulfate and chloride salinity than the Kesterson plants. The plants of both ecotypes accumulated about 90% of their total tissue Se in the nonprotein fraction. When sulfate was present in the irrigation solution, the Kesterson plants assimilated significantly less Se in its protein and nonprotein fractions than in the Bodega Bay plants. Under Se treatment, chlorosis symptoms were found on the leaves of the Bodega Bay plants, but not on the leaves of the Kesterson plants. The above results demonstrate that the two saltgrasses are distinct ecotypes in respect to their salinity tolerance and the ability of mitigation of selenium assimilation in the presence of sulfate.

Radiochemical separation of selenium from hydrochloric or hydrobromic acid into toluene

A separation of selenium based on the extraction of different concentrations of Se(IV) from 12 M hydrochloric acid or 8 M hydrobromic acid into toluene is described. Recoveries of 92% and 97%, respectively, are achieved in 7 min. Oxidizing agents interfere.