General Notices
FeSO4 -- 151.9 -- 13463-43-9
DEFINITION
Hydrated ferrous sulphate from which part of the water of hydration has been removed by drying.
Content: 86.0 per cent to 90.0 per cent.
CHARACTERS
Appearance: Greyish-white powder.
Solubility: Slowly but freely soluble in water, very soluble in boiling water, practically insoluble in ethanol (96 per cent).
It is oxidized in moist air, becoming brown.
IDENTIFICATION
A. It gives the reactions of sulphates.
B. It gives reaction (a) of iron.
C. It complies with the limits of the assay.
TESTS
Solution S: Dissolve 2.00 g in a 5 per cent V/V solution of lead-free nitric acid R and dilute to 100.0 ml with the same acid.
pH: 3.0 to 4.0.
Chlorides: Maximum 300 ppm.
Chromium: Maximum 1.00 × 102 ppm.
Copper:Maximum 50.0 ppm.
Ferric ions: Maximum 0.50 per cent.
Manganese: Maximum 0.10 per cent.
Nickel: Maximum 1.00 × 102 ppm.
Zinc: Maximum 1.00 × 102 ppm.
FeSO4.7H2O 278.02
Sulfuric acid, iron(2+) salt (1:1), heptahydrate.
Iron(2+) sulfate (1:1) heptahydrate [7782-63-0].
Anhydrous 151.91 [7720-78-7].
Ferrous Sulfate contains an amount of FeSO4 equivalent to not less than 99.5 percent and not more than 104.5 percent of FeSO4.7H2O.
Identification: It responds to the tests for Ferrous Salts 191 and for Sulfate 191 .
Arsenic: Transfer 1.0 g to a round-bottom, 100-mL flask fitted with a glass joint, add 40 mL of 9 N sulfuric acid and 2 mL of potassium bromide solution (3 in 10), and immediately connect the flask to a condenser having a matching glass joint and a reservoir with a water jacket that is cooled by ice-water. Heat the flask gently over a low flame until the solid dissolves, then distill until 25 mL of distillate collects in the reservoir. Transfer this distillate to the arsine generator flask, and wash the condenser and the reservoir with several small portions of water, adding the washings to the generator flask. Swirl to mix, add bromine until the color of the solution is slightly yellow, and dilute with water to 35 mL. The limit is 3 ppm.
Lead: the limit is 0.001%.
Mercury: It meets the requirement.
Dried Ferrous Sulfate USP Grade
FeSO4.xH2O
Sulfuric acid, iron(2+) salt (1:1), hydrate.
Iron(2+) sulfate (1:1) hydrate [13463-43-9].
Anhydrous 151.91 [7720-78-7].
Dried Ferrous Sulfate contains not less than 86.0 percent and not more than 89.0 percent of anhydrous ferrous sulfate (FeSO4).
Identification: It responds to the tests for Ferrous and Sulfate..
Insoluble substances: 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 105C: the weight of the insoluble residue does not exceed 1 mg (0.05%).
Arsenic: It meets the requirements of the test for Arsenic under Ferrous Sulfate.
Lead: the limit is 0.001%.
Mercury: It meets the requirements.
FeSO4·7H2O Formula weight 278.02
CAS: [7782-63-0]
DESCRIPTION
Ferrous Sulfate occurs as pale, blue-green crystals or granules that are efflorescent in dry air. In moist air, it oxidizes readily to form a brown-yellow, basic ferric sulfate. A 1:10 aqueous solution has a pH of about 3.7. One gram dissolves in 1.5 mL of water at 25° and in 0.5 mL of boiling water. It is insoluble in alcohol.
Function: Nutrient.
REQUIREMENTS
Identification: A sample gives positive tests for Ferrous Salts (Iron) and for Sulfate.
Assay: Not less than 99.5% and not more than 104.5% of FeSO4·7H2O.
Lead: Not more than 2 mg/kg.
Mercury: Not more than 1 mg/kg.
FeSO4·xH2O Formula weight, anhydrous 151.91
CAS: [7720-78-7]
DESCRIPTION
Ferrous Sulfate, Dried, occurs as a gray-white to buff colored powder consisting primarily of FeSO4·H2O, with varying amounts of FeSO4·4H2O. It dissolves slowly in water, but is insoluble in alcohol.
Function: Nutrient.
REQUIREMENTS
Identification: A sample gives positive tests for Ferrous Salts (Iron) and for Sulfate.
Assay: Not less than 86.0% and not more than 89.0% of FeSO4.
Insoluble Substances: Not more than 0.05%.
Lead: Not more than 2 mg/kg.
Mercury: Not more than 1 mg/kg.
