NaNO2 69.00

Nitrous acid,sodium salt.
Sodium nitrite [7632-00-0].

Packaging and storage— Preserve in tight containers.Store at 25,excursions permitted between 15and 30.

Identification— Asolution of it responds to the tests for Sodium á191ñand for Nitrite á191ñ.

Loss on drying á731ñ— Dry it over silica gel for 4hours:it loses not more than 0.25%of its weight.

Heavy metals á231ñ— Dissolve 1g in 6mLof 3Nhydrochloric 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 23mLof water,and add 2mLof 1Nacetic acid:the limit is 0.002%.

Assay— Dissolve about 1g of Sodium Nitrite,accurately weighed,in water to make 100.0mL.Pipet 10mLof this solution into a mixture of 50.0mLof 0.1Npotassium permanganate VS,100mLof water,and 5mLof 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 5minutes,and add 25.0mLof 0.1Noxalic acid VS.Heat the mixture to about 80,and titrate with 0.1Npotassium permanganate VS.Each mLof 0.1Npotassium permanganate is equivalent to 3.450mg of NaNO2.

Expert Committee:(PA5)Pharmaceutical Analysis 5

USP28–NF23Page 1789

Phone Number:1-301-816-8305