Cupric Sulfate
CuSO4·5H2O 249.69

Sulfuric acid, copper(2+) salt (1:1), pentahydrate.
Copper(2+) sulfate (1:1) pentahydrate [7758-99-8].

Anhydrous 159.61 [7758-98-7].
» Cupric Sulfate, dried at 250 to constant weight, contains not less than 98.5 percent and not more than 100.5 percent of CuSO4.
Packaging and storage— Preserve in tight containers. Store at 25, excursions permitted between 15 and 30.
Identification— A solution (1 in 10) responds to the tests for Copper 191 and for Sulfate 191.
Loss on drying 731— Dry it at 250 to constant weight: it loses between 33.0% and 36.5% of its weight.
Limit of sodium—
Stock solution— Transfer 40.0 g of Cupric Sulfate to a 200-mL volumetric flask, add water, and swirl to dissolve. Add 5 mL of nitric acid, dilute with water to volume, and mix. This solution contains 0.2 g of cupric sulfate per mL.
Test solutions— To three 25-mL volumetric flasks add a volume of Stock solution equivalent to the weight of test specimen given in the accompanying table. To two of the flasks add the amounts of reference analyte ion specified in the accompanying table. Add 2 mL of potassium chloride solution (1 in 20) to each flask, dilute with water to volume, and mix.
Procedure— Using atomic absorption spectrophotometry (see Spectrophotometry and Light-Scattering 851), analyze the Test solutions by the method of standard addition analysis according to the accompanying table. The limit is 0.02%.
Limit of potassium—
Stock solution— Use the Stock solution prepared in the test for Limit of sodium.
Test solutions— To three 25-mL volumetric flasks add a volume of Stock solution equivalent to the weight of test specimen given in the accompanying table. To two of the flasks add the amounts of reference analyte ion specified in the accompanying table, dilute with water to volume, and mix.
Procedure— Using atomic absorption spectrophotometry (see Spectrophotometry and Light-Scattering 851), analyze the Test solutions by the method of standard addition analysis according to the accompanying table. The limit is 0.01%.
Limit of calcium—
Stock solution— Use the Stock solution prepared in the test for Limit of sodium.
Test solutions— To three 25-mL volumetric flasks add a volume of Stock solution equivalent to the weight of test specimen given in the accompanying table. To two of the flasks add the amounts of reference analyte ion specified in the accompanying table, dilute with water to volume, and mix.
Procedure— Using atomic absorption spectrophotometry (see Spectrophotometry and Light-Scattering 851), analyze the Test solutions by the method of standard addition analysis according to the accompanying table. The limit is 0.005%.
Limit test Wavelength
(nm)		 Test specimen
weight (g)		 Reference ion
added (mg)		 Flame type Background
correction
Sodium 589.0 0.05 0.005/0.01 air–acetylene No
Potassium 766.5 0.4 0.02/0.04 air–acetylene No
Calcium 422.7 0.8 0.02/0.04 nitrous oxide–acetylene No
Iron 248.3 4.0 0.12/0.24 air–acetylene Yes
Nickel 232.0 4.0 0.10/0.20 air–acetylene No
Limit of iron—
Stock solution— Use the Stock solution prepared in the test for Limit of sodium.
Test solutions— To three 25-mL volumetric flasks add a volume of Stock solution equivalent to the weight of test specimen given in the accompanying table. To two of the flasks add the amounts of reference analyte ion specified in the accompanying table, dilute with water to volume, and mix.
Procedure— Using atomic absorption spectrophotometry (see Spectrophotometry and Light-Scattering 851), analyze the Test solutions by the method of standard addition analysis according to the accompanying table. The limit is 0.003%.
Limit of nickel—
Stock solution— Use the Stock solution prepared in the test for Limit of sodium.
Test solutions— To three 25-mL volumetric flasks add a volume of Stock solution equivalent to the weight of test specimen given in the accompanying table. To two of the flasks add the amounts of reference analyte ion specified in the accompanying table, dilute with water to volume, and mix.
Procedure— Using atomic absorption spectrophotometry (see Spectrophotometry and Light-Scattering 851), analyze the Test solutions by the method of standard addition analysis according to the accompanying table. The limit is 0.005%.
Limit test Wavelength
(nm)		 Test specimen
weight (g)		 Reference ion
added (mg)		 Flame type Background
correction
Sodium 589.0 0.05 0.005/0.01 air-acetylene No
Potassium 766.5 0.4 0.02/0.04 air-acetylene No
Calcium 422.7 0.8 0.05/0.10 air-acetylene No
Iron 248.3 4.0 0.12/0.24 air-acetylene Yes
Nickel 232.0 4.0 0.10/0.20 air-acetylene No
Assay— Place about 650 mg of Cupric Sulfate in an accurately weighed container fitted with a ground-glass stopper, dry, allow to cool in a desiccator, and weigh again to obtain the weight of the specimen. Dissolve in 50 mL of water, add 4 mL of 6 N acetic acid and 3 g of potassium iodide, and titrate the liberated iodine with 0.1 N sodium thiosulfate VS, adding about 2 g of potassium thiocyanate and 3 mL of starch TS as the endpoint is approached. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium thiosulfate is equivalent to 15.96 mg of CuSO4.
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Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
1-301-816-8394		 (MDAA05) Monograph Development-Antivirals and Antimicrobials
USP32–NF27 Page 2034
Pharmacopeial Forum: Volume No. 33(5) Page 898
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.