Nitrate
描述
In inorganic chemistry, a nitrate is a salt of nitric acid. In organic chemistry the esters of nitric acid and various alcohols are called nitrates. The nitrate ion is a polyatomic anion with the empirical formula NO3- and a molecular mass of 62.01 daltons; it consists of one central nitrogen atom surrounded by three identical oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a negative one formal charge. Nitrates should not be confused with nitrites, the salts of nitrous acid. Organic compounds containing the nitro functional group (which has the same formula and structure as the nitrate ion save that one of the O2 atoms is replaced by the R group) are known as nitro compounds. Nitrate ions can be toxic. In particular, nitrate toxicosis in humans occurs through enterohepatic metabolism of nitrates to ammonia, with nitrite being an intermediate. Nitrites oxidize the iron atoms in hemoglobin from Ferrous Iron (2+) to Ferric Iron (3+), rendering it unable to carry oxygen. This condition is called methemoglobinemia and can lead to a lack of oxygen in tissues. Methemoglobinemia can be treated with methylene blue. -- Wikipedia.
类别
"Pesticide", "Household Toxin", "Food Toxin", "Natural Toxin"
同义词
"Nitrate ion", "Nitrate(1-)", "Nitric acid", "Trioxidonitrate", "Trioxidonitrate(1-)", "Trioxonitrate", "Trioxonitrate(1-)"
InChI 标识符
InChI=1S/NO3/c2-1(3)4/q-1
键
InChIKey=NHNBFGGVMKEFGY-UHFFFAOYSA-N
化合物类型
Inorganic compounds
大分类
Homogeneous non-metal compounds
类型
Non-metal oxoanionic compounds
取代基
"Inorganic oxide", "Non-metal nitrate"
外部描述符
"an anion", "monovalent inorganic anion", "nitrogen oxoanion", "reactive nitrogen species"
地位
Detected and Not Quantified
蜂窝位置
"Cytoplasm", "Extracellular"
组织位置
"Adipose Tissue", "Bladder", "Epidermis", "Fibroblasts", "Heart", "Intestine", "Kidney", "Lung", "Myelin", "Nerve Cells", "Neuron", "Pancreas", "Platelet", "Skeletal Muscle", "Spleen", "Stratum Corneum", "Testes", "Thyroid Gland"
熔点/沸点/溶解度
73°C (163.4°F)//
暴露途径
Oral (L1137) ; inhalation (L1137)
毒性机制
Nitrate's toxicity is a result of it's conversion to nitrite once in the body. Nitrite causes the autocatalytic oxidation of oxyhemoglobin to hydrogen peroxide and methemoglobin. This elevation of methemoglobin levels is a condition known as methemoglobinemia, and is characterized by tissue hypoxia, as methemoglobin cannot bind oxygen. (A2450, L1613)
代谢
Intake of some amount of nitrates and nitrites is a normal part of the nitrogen cycle in humans. In vivo conversion of nitrates to nitrites can occur in the gastrointestional tract under the right conditions, significantly enhancing nitrates' toxic potency. The major metabolic pathway for nitrate is conversion to nitrite, and then to ammonia. Nitrites, nitrates, and their metabolites are excreted in the urine. (L1137)
毒性值
LD50: 138 ppm over 30 minutes (Inhalation, Rat) (A677)
致癌性
Ingested nitrate or nitrite under conditions that result in endogenous nitrosation is probably carcinogenic to humans (Group 2A). (L135)
用途/来源
Nitrates and nitrites are naturally produced and may also be found in pesticides. Exposure usually occurs from contact with contaminated soil, food water. Nitrates may also be found in certain drugs. (L1137)
健康影响
Nitrate and nitrite poisoning causes methemoglobinemia. Nitrites may cause pregnancy complications and developmental effects. They may also be carcinogenic. (L1137)
症状
Nitrate and nitrite poisoning causes methemoglobinemia. Symptoms include cyanosis, cardiac dysrhythmias and circulatory failure, and progressive central nervous system (CNS) effects. CNS effects can range from mild dizziness and lethargy to coma and convulsions. (L1137)
治疗
Methemoglobinemia can be treated with supplemental oxygen and methylene blue 1% solution administered intravenously slowly over five minutes followed by IV flush with normal saline. Methylene blue restores the iron in hemoglobin to its normal (reduced) oxygen-carrying state. (L1613)
维基百科链接
http://en.wikipedia.org/wiki/Nitrate
创建于
2009-03-06 18:58:18 UTC
更新于
2014-12-24 20:21:21 UTC