Assay
Pipet an accurately measured volume of Injection, containing about 150 mg of sodium nitrite into a mixture of 50.0 mL of 0.1 N potassium permanganate VS, 100 mL of water, and 5 mL of sulfuric acid, immersing the tip of the pipet beneath the surface of the mixture during the addition. 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.