ASSAY ON SODIUM NITRITE ABSTRACT- The official U.S.P. assay for sodium nitrite which employs standard permanganate and standard oxalate solutions is compared with a new method using standard ceric sulfate solution. The proposed method is shown to be more accurate than the official method by comparison of the results with the absolute purity of the sodium nitrite determined by phase solubility analysis. The official N.F. XI method for sodium nitrite tablets involving determination of chloride produced by reduction of potassium chlorate is shown to give unacceptable precision. 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 NaNO2.

1. ASSAY ON SODIU
M NITRITE
Alternate Presentations

2. Contents 1. Abstract
2. Introduction
3. Assay
4. Reference

3. ABSTRACT
The official U.S.P. assay for sodium nitrite which employs standard permangan
ate and standard oxalate solutions is compared with a new method using stand
ard ceric sulfate solution. The proposed method is shown to be more accurate t
han the official method by comparison of the results with the absolute purity of t
he sodium nitrite determined by phase solubility analysis. The official N.F. XI me
thod for sodium nitrite tablets involving determination of chloride produced by re
duction of potassium chlorate is shown to give unacceptable precision.

4. Sodium Nitrite
NaNO2 69.00
Nitrous acid, sodium salt. Sodium nitrite [7632-00-0].
» Sodium Nitrite contains not less than 97.0 percent and not
more than 101.0 percent of NaNO2, calculated on the dried b
asis.

5. Packaging and storage- Preserve in tight containers. Sto
re at 25°, excursions permitted between 15 and 30.
Identification- A solution of it responds to the tests for Sodi
um
(191) and for Nitrite (191>.

6. Loss on drying. 731- Dry it over silica gel for 4 hours: it los
es not more than 0.25% of its weight.
Heavy metals (231) - Dissolve 1 g in 6 mL of 3 N hydrochl
oric 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 per
ceptible. Dissolve the residue in 23 mL of water, and add 2 m
L of 1 N acetic acid: the limit is 0.002%.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)

7. ASSAY
Assay- Dissolve about 1 g of Sodium Nitrite, accurately weig
hed, in water to make 100.0 mL. Pipet 10 mL of this solution i
nto a mixture of 50.0 mL of 0.1 N potassium permanganate V
S, 100 mL of water, and 5 mL of sulfuric acid. When adding th
e Sodium Nitrite solution, immerse the tip of the pipet beneat
h the surface of the permanganate mixture. Warm the liquid t
o 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 wi
th 0.1 N potassium permanganate VS. Each mL of 0.1 N pota
ssium permanganate is equivalent to 3.450 mg of NaNO2.

8. REFERENCES
1. https://pubchem.ncbi.nlm.nih.gov/compoundsodiumnitrite
2. Abstract: uckerman, M. M., et ol., J. Pharm. Sci., 53, 682 (1964).
3. “United States Pharmacopeia,” 16th rev., Mack Publishing Co. Easton Pa.
1960 p. 1082
4. Journal of pharmaceutical sciences : https://doi.org/10.1002/jps.260054062
0

9. Thank you