Packaging and storage
Preserve in well-closed containers.
It responds to the tests for Ferrous Salts 191
and for Sulfate 191
Dissolve 2.0 g in 20 mL of freshly boiled dilute sulfuric acid (1 in 100), heat to boiling, and digest in a covered beaker on a steam bath for 1 hour. Filter through a tared filtering crucible, wash thoroughly, and dry at 105
: the weight of the insoluble residue does not exceed 1 mg (0.05%).
Using Dried Ferrous Sulfate, proceed as directed in the test for Lead
under Ferrous Sulfate:
the limit is 0.001%.
Organic volatile impurities, Method IV 467:
meets the requirements.
Dissolve about 800 mg of Dried Ferrous Sulfate, accurately weighed, in a mixture of 25 mL of 2 N sulfuric acid and 25 mL of freshly boiled and cooled water. Add orthophenanthroline TS
, and immediately titrate with 0.1 N ceric sulfate VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N ceric sulfate is equivalent to 15.19 mg of anhydrous ferrous sulfate (FeSO4