Packaging and storage
Preserve in tight containers. Store at 25
, excursions permitted between 15
and 30
.
Identification
A solution of it responds to the tests for
Sodium 191 and for
Nitrite 191.
Loss on drying 731
Dry it over silica gel for 4 hours: it loses not more than 0.25% of its weight.
Heavy metals 231
Dissolve 1 g in 6 mL of 3 N hydrochloric acid, and evaporate on a steam bath to dryness. Reduce the residue to a coarse powder, and continue heating on the steam bath until the odor of hydrochloric acid no longer is perceptible. Dissolve the residue in 23 mL of water, and add 2 mL of 1 N acetic acid: the limit is 0.002%.
Assay
Dissolve about 1 g of Sodium Nitrite, accurately weighed, in water to make 100.0 mL. Pipet 10 mL of this solution into a mixture of 50.0 mL of 0.1 N potassium permanganate VS, 100 mL of water, and 5 mL of sulfuric acid. When adding the Sodium Nitrite solution, immerse the tip of the pipet beneath the surface of the permanganate mixture. Warm the liquid to 40
, allow it to stand for 5 minutes, and add 25.0 mL of 0.1 N oxalic acid VS. Heat the mixture to about 80
, and titrate with 0.1 N potassium permanganate VS. Each mL of 0.1 N potassium permanganate is equivalent to 3.450 mg of NaNO
2.