Packaging and storage—
Preserve in tight containers.
Labeling—
Label the Tablets in terms of ferrous sulfate (FeSO4·7H2O) and in terms of elemental iron.
Identification—
Dissolve a quantity of powdered Tablets, equivalent to about 250 mg of ferrous sulfate, in sufficient water, acidified with hydrochloric acid, to make 25 mL of solution: the solution responds to the tests for
Ferrous Salts 
191
and for
Sulfate 191.
Dissolution 711—
Medium:
0.1 N hydrochloric acid; 900 mL.
Apparatus 2:
50 rpm.
Time:
45 minutes.
Procedure—
Determine the amount of FeSO4·7H2O dissolved, employing atomic absorption spectrophotometry at a wavelength of about 248.3 nm on filtered portions of the solution under test, suitably diluted with Dissolution Medium if necessary, in comparison with a Standard solution having a known concentration of iron in the same medium.
Tolerances—
Not less than 75% (Q) of the labeled amount of FeSO4·7H2O is dissolved in 45 minutes.
Assay—
Weigh and finely powder not fewer than 20 Tablets. Dissolve a portion of the powder, equivalent to about 500 mg of ferrous sulfate and accurately weighed, in a beaker containing a mixture of 20 mL of 2 N sulfuric acid and 80 mL of freshly boiled and cooled water. Filter the solution rapidly as soon as all soluble ingredients in the tablets are dissolved, and wash the container and the filter with small portions of a mixture of 20 mL of 2 N sulfuric acid and 80 mL of freshly boiled and cooled water. Add
orthophenanthroline TS, and immediately titrate the combined filtrate and washings with 0.1 N ceric sulfate VS. Each mL of 0.1 N ceric sulfate is equivalent to 27.80 mg of ferrous sulfate (FeSO
4·7H
2O).
