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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 ...
The US Food and Drug Administration approved a selenium supplement to animal diets; the most common form is sodium selenite for pet foods. According to one article, "not much was known about which selenium compounds to approve for use in animal feeds when the decisions were made back in the 1970s ..
[3] [4] It is suitable for food and laboratory uses. Reagent grade is almost as stringent as the ACS grade. USP grade meets the purity levels set by the United States Pharmacopeia (USP). USP grade is equivalent to the ACS grade for many drugs. NF grade is a purity grade set by the National Formulary (NF). NF grade is equivalent to the ACS grade ...
The USP is published in a combined volume with the National Formulary (a formulary) as the USP-NF. [2] If a drug ingredient or drug product has an applicable USP quality standard (in the form of a USP-NF monograph), it must conform in order to use the designation "USP" or "NF".
Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate (K 2 SeO 4) and sulfur trioxide (SO 3). [7] Salts of selenous acid are called selenites. These include silver selenite (Ag 2 SeO 3) and sodium selenite (Na 2 SeO 3). Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide:
SeO 2 is considered an acidic oxide: it dissolves in water to form selenous acid. [6] Often the terms selenous acid and selenium dioxide are used interchangeably. It reacts with base to form selenite salts containing the SeO 2− 3 anion. For example, reaction with sodium hydroxide produces sodium selenite: SeO 2 + 2 NaOH → Na 2 SeO 3 + H 2 O
Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate (K 2 SeO 4) and sulfur trioxide (SO 3). [25] Salts of selenous acid are called selenites. These include silver selenite (Ag 2 SeO 3) and sodium selenite (Na 2 SeO 3). Hydrogen sulfide reacts with aqueous selenous acid to produce selenium disulfide:
A laboratory specimen is sometimes a biological specimen of a medical patient's tissue, fluids, or other samples used for laboratory analysis to assist in differential diagnosis or staging of a disease process. These specimens are often the most reliable method of diagnosis, depending on the ailment.