The determination methods of nitrite are Nessler's reagent method and iron sulfate method.

Nitrite

Nitrite is a salt containing nitrite anion (NO2?). The most common one is sodium nitrite, which is white to light yellow powder or granular. It tastes slightly salty and is easily soluble in water.

Nitrate and nitrite are widely present in the human environment and are the most common nitrogen-containing compounds in nature. Nitrate in the human body can be reduced to nitrite and the precursor of N-nitroso compounds under the action of microorganisms.

It looks and tastes similar to table salt and is widely used in industry and construction. It is also allowed to be used as a coloring agent in meat products in a limited amount. The probability of food poisoning caused by nitrite is high. Nitrite food poisoning is also known as enterogenic cyanosis, cyanosis, and black mouth disease.

Knowledge expansion:

Nitrite poisoning refers to poisoning caused by eating cured meat products, pickles and spoiled vegetables with high nitrate or nitrite content, or Caused by mistakenly consuming industrial sodium nitrite as table salt.

It can also be seen after drinking bitter well water or steamer water containing nitrates or nitrites. Nitrite can oxidize the low-iron hemoglobin that normally carries oxygen in the blood into methemoglobin, thus losing the ability to carry oxygen. ability to cause tissue hypoxia. Nitrite is a highly toxic substance. Ingestion of 0.2 to 0.5 grams by adults can cause poisoning, and 3 grams can cause death.

At the same time, there is a positive correlation between esophageal cancer and the amount of nitrite ingested by patients. The carcinogenic mechanism of nitrite is: nitrite interacts with secondary amines, tertiary amines and amides in food in environments such as gastric acid. The reaction produces nitrosamines, a strong carcinogen. Nitrosamines can also enter the fetus through the placenta and have teratogenic effects on the fetus.

As a color-protecting agent for meat products, nitrite can react with the myoglobin in the meat to form rose-colored nitrosomyoglobin, which improves the color of the meat; it can also enhance the flavor and preservative of the meat. It acts as an agent to prevent the growth of Clostridium botulinum and extend the shelf life of meat products.

It is worth noting that high doses of nitrite can still cause great toxicity. Accidentally eating nitrite can cause nitrite food poisoning, and long-term use can even cause esophageal cancer and gastric cancer.