What Is Nitrite?
Nitrite is a salt containing the nitrite ion NO2-.
Nitrite is reduced to nitric oxide under low carbon, and nitric oxide is said to be necessary for life. On the other hand, when nitrite reacts with amines contained in proteins, nitrosamines are produced, and nitrosamines are said to be highly carcinogenic.
People are warned not to consume nitrite and amines at the same time. The International Agency for Research on Cancer (IRAC) has also classified nitrosamines as possibly carcinogenic to humans (Group 2A).
Typical examples of nitrite are sodium nitrite and potassium nitrite.
Uses of Nitrites
A urine test for the presence of nitrite can be found in the urine. Nitrites, which are usually ingested mainly from vegetables, are eliminated from the body if nothing is wrong.
However, when bacteria grow in the urinary tract due to infection, such as cystitis, nitrate is converted to nitrite by the bacteria, and when nitrite is detected in the urine test, it is possible to determine whether a urinary tract infection is present.
Nitrite is also used as a coloring agent and preservative in ham and sausage, but there are limits on the amount of nitrite used, as it can cause poisoning symptoms if too much is ingested into the body.
Properties of Nitrites
Under hypoxic conditions, nitrite releases nitric oxide, which has vasodilatory properties. The conversion of nitrite to nitric oxide is an enzymatic reduction by mitochondria, xanthine oxidoreductase, and nitric oxide synthase. Many bacteria reduce nitrite to nitric oxide and ammonia.
Nitrites are salts with NO2-, the nitrite ion. That is, nitrite ion, nitrite salt, or nitrite ester.
Complexes of nitrite ions can act as ambident ligands. For example, when it coordinates with an oxygen atom, it is called nitrite, and when it coordinates with a nitrogen atom, it is called nitro.
Other Information About Nitrites
1. How to Synthesize Nitrites
Nitrites of alkali metals and alkaline earth metals can be synthesized by reacting a mixture of nitric oxide or nitrogen dioxide with the hydroxide of the corresponding metal. In contrast, they can also be synthesized by the thermal decomposition of the corresponding nitrates. Otherwise, nitrite can be synthesized by reduction of the corresponding nitrates.
2. Regulatory Limits for Nitrites
Nitrite is sometimes included in water quality standards for nitrite-nitrogen, and there are differences in nitrite-converted and nitrite-nitrogen-equivalent values depending on the region. The conversion formula can be expressed as “nitrite nitrogen” concentration (mgN/L) = Nitrite concentration (mg/L) × 14/46.
Specifically, in addition to Japan, the United States, Singapore, and other countries use the nitrite nitrogen conversion value. In Japan, the sum of nitrate and nitrite ion was set at 10 mg/L and nitrite ion alone at 0.05 mg/L in the items of tap water standards and environmental standards. Water quality standard values pertaining to nitrite-nitrogen have since been added.
3. Characteristics of Sodium Nitrites
Sodium nitrite is a sodium nitrite, often abbreviated as sodium nitrite or sodium nitrite. Its chemical formula is NaNO2, which is a white or yellow orthorhombic crystal. Sodium nitrite is hygroscopic and deliquescent, and when dissolved in water, the aqueous solution becomes alkaline.
4. Characteristics of Potassium Nitrites
Potassium nitrite is a nitrite of potassium, with the chemical formula KNO2. Like sodium nitrite, it is used overseas as a food preservative. It is used in a wide range of applications, most notably in wastewater treatment and in the manufacture of metal oxide membranes for fuel cells.