Nitrites usually are prepared by absorption of nitric oxide and nitrogen dioxide in an alkaline solution. In an older method, sodium nitrate was fused with lead, and the resulting sodium nitrite was dissolved in water and separated from the by-product, lead oxide, by filtration.

How are nitrites formed?

Nitrite is formed by the oxidation of ammonia by ammonia-oxidizing bacteria (AOB). It is toxic to shrimp, although less so than ammonia, especially in saline water.

Where do nitrites come from?

Approximately 80% of dietary nitrates are derived from vegetable consumption; sources of nitrites include vegetables, fruit, and processed meats. Nitrites are produced endogenously through the oxidation of nitric oxide and through a reduction of nitrate by commensal bacteria in the mouth and gastrointestinal tract.