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Selenium is toxic in high concentrations. As sodium selenite, the chronic toxic dose for human beings was described as about 2.4 to 3 milligrams of selenium per day. [7] In 2000, the US Institute of Medicine set the adult Tolerable upper intake levels (UL) for selenium from all sources - food, drinking water and dietary supplements - at 400 μg/day. [8]
Owing to its similarity to sulfur-containing methionine, selenomethionine is mistaken for an amino acid by the yeast anabolism and incorporated in its proteins. It has been claimed that selenomethionine makes a better source of dietary selenium in animal nutrition, since it is an organic chemical compound sometimes found in some common crops ...
In solution it ionizes to HSe −. The selenide dianion Se 2− forms a variety of compounds, including the minerals from which selenium is obtained commercially. Illustrative selenides include mercury selenide (HgSe), lead selenide (PbSe), zinc selenide (ZnSe), and copper indium gallium diselenide (Cu(Ga,In)Se 2). These materials are ...
Sodium selenate is produced by oxidation of selenium, first with nitric acid, producing selenous acid. The selenous acid is neutralized to form sodium selenite. The sodium selenite is oxidized in a basic medium hydrogen peroxide to form a selenate, which is then spray-dried. [3] Se + 2HNO 3 → H 2 SeO 3 + NO + NO 2 H 2 SeO 3 + Na 2 CO 3 → Na ...
Selenomethionine is readily available as a dietary supplement. It has been suggested by nutritionists that selenomethionine, as an organic form of selenium, is easier for the human body to absorb than selenite, which is an inorganic form. [8] It was determined in a clinical trial that selenomethionine is absorbed 19% better than selenite. [8]
The most common artificial nutrient solution is the Hoagland solution, developed by D. R. Hoagland and W. C. Snyder in 1933. The solution (known as A-Z solution) consists of all the essential macro- and micronutrients in the correct proportions necessary for most plant growth. [6] An aerator is used to prevent an anoxic event or hypoxia.
The main difference between solution (1) and solution (2) is the different use of nitrate-nitrogen and ammonium-nitrogen based stock solutions to prepare the respective Hoagland solution of interest. Accordingly, the original 1933 and the modified concentrations of 1938 and 1950 for each essential element and sodium are shown below, the ...
A selenate selenite is a chemical compound or salt that contains selenite and selenate anions (SeO 3 2-and SeO 4 2-). These are mixed anion compounds . Some have third anions.