nitritet

Nitritet, or nitrite (NO2−), is an inorganic anion that forms when nitrous acid (HNO2) loses a proton. In solution it exists in equilibrium with nitrous acid, and its chemistry is influenced by pH and redox conditions. Nitrite can act as both an oxidant and a reductant in different reactions and is readily oxidized to nitrate (NO3−) in the presence of oxygen.

Nitrite occurs naturally in soils and water as part of the nitrogen cycle, produced by bacterial reduction of nitrate and by nitrification processes. Industrially, nitrite salts such as sodium nitrite (NaNO2) and potassium nitrite (KNO2) are prepared for use as reagents and, in some cases, as food additives.

Applications of nitrite include its use as a curing agent in processed meats to inhibit microbial growth, preserve color, and extend shelf life. In chemistry and biochemistry, nitrite serves as a reagent and intermediate in various redox reactions and diazotization processes. It also functions as an analytical indicator in some assays.

Health and safety considerations are important. High nitrite intake can cause methemoglobinemia, particularly in infants, by reducing the blood’s oxygen-carrying capacity. Nitrite can react with secondary amines to form nitrosamines, compounds suspected to be carcinogenic. Consequently, regulatory authorities limit nitrite levels in foods and drinking water to protect public health.

Environmental aspects include nitrite’s toxicity to aquatic organisms at elevated concentrations and its appearance in water systems through agricultural runoff and wastewater discharge. In natural ecosystems, nitrite participates in the broader nitrogen cycle, being interconverted with nitrate and nitrogen gas through microbial processes.