It was found that heating of diluted nitric or hydrochloric acids in many years stored glass beakers can result in mBq quantities
of 210Po leached from beaker walls to the solution. In the case of freshly bought beakers acid leaching of 210Po was not observed. We suppose that acid leachable 210Po in old beakers is mainly due to implantation of radon progenies (from air) into superficial layers of glass beaker walls.
Four composite materials with di-(2-ethylhexyl) phosphoric acid (HDEHP) as an extraction agent and PAN as a binding polymer
were studied in this work. The intended use of these materials is in extraction chromatography. They were prepared by various
methods and contained different amounts of HDEHP. The properties were compared by studying europium uptake from nitric acid
solutions. Materials prepared by direct incorporation of extraction agent into PAN polymer during beads production and with
up to 40% (w/w) of HDEHP are suitable for analytical separations. Materials with high capacity can be prepared by impregnation
of ready-made PAN beads.
Authors:C. Galinha, M. Freitas, A. Pacheco, J. Kameník, J. Kučera, H. Anawar, J. Coutinho, B. Maçãs, and A. Almeida
Selenium (Se) is an essential micronutrient for human health but it is deficient in at least 1 billion people around the globe.
Cereals are by far the most significant agricultural crops, not only on a gross tonnage basis, but also by what they represent
in terms of energy supply and dietary intake for human nutrition worldwide. Portugal is no exception to such pattern. The
Portuguese situation is difficult to assess though, due to scarce information and lack of consistent studies on the subject.
In these terms, the Se status of major cereals and their cultivation soils are dealt with herein. Two species of wheat–bread
and durum wheat–were sown at the end of November 2009, and then sampled in different growth stages. Rye was collected during
harvest season, and cultivation soils were analyzed as well. Se results were within the range of: 100–225 ng g−1 for soils; 3–55 ng g−1 for durum wheat; 6–80 ng g−1 for bread wheat; and 4–30 ng g−1 for rye. Accuracy of the RNAA procedure was proved by analysis of reference materials NIST-SRM 1515 and NIST-SRM 8433.