Nitriten

Nitriten is a term used for nitrite compounds, including the nitrite ion NO2− and its salts and esters. The nitrite ion arises from nitrous acid (HNO2) and carries a −1 charge, with nitrogen in the +3 oxidation state. In practice, nitriten most commonly appear as inorganic salts such as sodium nitrite (NaNO2) and potassium nitrite (KNO2), as well as organic nitrite esters used in various chemical applications.

Chemically, NO2− is a weak base and a reductant under certain conditions. In aqueous solution it exists in equilibrium with nitrous acid HNO2, with a pKa around 3.3, meaning that at neutral pH most nitrite is present as NO2−. Nitriten can participate in oxidation-reduction reactions, and they can be reduced to nitric oxide (NO), nitrous oxide (N2O), or nitrogen gas (N2) by biological or chemical processes.

Natural occurrence and uses: Nitrites are intermediates in the global nitrogen cycle, formed during the microbial oxidation of ammonia to nitrite (nitrification) and during the reduction of nitrate and nitrite to nitrogen gases (denitrification). Industrially, nitriten are produced and used as curing agents in meat processing, as corrosion inhibitors, and as reagents in organic synthesis.

Health and safety: Elevations in nitrite levels can cause methemoglobinemia, a condition that impairs the blood’s ability to transport oxygen. Food-grade nitrites are regulated to limit health risks, and nitrite-containing foods are monitored in many jurisdictions. In some settings nitrite can contribute to the formation of nitrosamines, compounds of concern for cancer risk.

Environmental aspects: Nitrite can enter water systems through agricultural runoff and wastewater. At sufficient concentrations, nitrite can be toxic to aquatic life and can affect ecosystem balance. Monitoring methods include colorimetric and electrochemical detection.