0.1 M Sodium Nitrite VS
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
NaNO2, 69.00
6.900 g in 1000 mL
Dissolve 6.9 g of sodium nitrite in water to make 1000 mL.
Standardization: Accurately weigh about 500 mg of USP Sulfanilamide RS, previously dried at 105° for 3 h, and transfer to a suitable beaker. Add 20 mL of hydrochloric acid and 50 mL of water, stir until dissolved, and cool to 15°. Maintaining the temperature at about 15°, titrate slowly with the sodium nitrite solution, placing the buret tip below the surface of the solution to preclude air oxidation of the sodium nitrite, and stir the solution gently with a magnetic stirrer, but avoid pulling a vortex of air beneath the surface. Use the indicator specified in the individual monograph, or, if a potentiometric procedure is specified, determine the endpoint electrometrically using platinum-calomel or platinum-platinum electrodes. When the titration is within 1 mL of the endpoint, add the titrant in 0.1-mL portions, and allow 1 min between additions. Each 17.22 mg of sulfanilamide is equivalent to 1 mL of 0.1000 M sodium nitrite.
M = mg of sulfanilamide/(172.20 x mL NaNO2)
[NOTE-If this volumetric solution is used in a qualitative application such as pH adjustment, dissolution medium, or diluent, its standardization is not required.]
