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 250to constant weight,contains not less than 98.5percent and not more than 100.5percent of CuSO4.
Packaging and storage— Preserve in tight containers.Store at 25,excursions permitted between 15and 30.
Identification— Asolution (1in 10)responds to the tests for Copper á191ñand for Sulfate á191ñ.
Loss on drying á731ñ— Dry it at 250to constant weight:it loses between 33.0%and 36.5%of its weight.
Limit of sodium—
Stock solution— Transfer 40.0g of Cupric Sulfate to a 200-mLvolumetric flask,add water,and swirl to dissolve.Add 5mLof nitric acid,dilute with water to volume,and mix.This solution contains 0.2g of cupric sulfate per mL.
Test solutions— To three 25-mLvolumetric flasks add a volume of Stock solutionequivalent 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 2mLof potassium chloride solution (1in 20)to each flask,dilute with water to volume,and mix.
Procedure— Using atomic absorption spectrophotometry (see Spectrophotometry and Light-Scattering á851ñ),analyze the Test solutionsby the method of standard addition analysis according to the accompanying table.The limit is 0.02%.
Limit of potassium—
Stock solution— Use the Stock solutionprepared in the test for Limit of sodium.
Test solutions— To three 25-mLvolumetric flasks add a volume of Stock solutionequivalent 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 á851ñ),analyze the Test solutionsby the method of standard addition analysis according to the accompanying table.The limit is 0.01%.
Limit of calcium—
Stock solution— Use the Stock solutionprepared in the test for Limit of sodium.
Test solutions— To three 25-mLvolumetric flasks add a volume of Stock solutionequivalent 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 á851ñ),analyze the Test solutionsby the method of standard addition analysis according to the accompanying table.The limit is 0.005%.
Limit of iron—
Stock solution— Use the Stock solutionprepared in the test for Limit of sodium.
Test solutions— To three 25-mLvolumetric flasks add a volume of Stock solutionequivalent 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 á851ñ),analyze the Test solutionsby the method of standard addition analysis according to the accompanying table.The limit is 0.003%.
Limit of nickel—
Stock solution— Use the Stock solutionprepared in the test for Limit of sodium.
Test solutions— To three 25-mLvolumetric flasks add a volume of Stock solutionequivalent 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 á851ñ),analyze the Test solutionsby 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
Organic volatile impurities,Method IVá467ñ: meets the requirements.
Assay— Place about 650mg 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 50mLof water,add 4mLof 6Nacetic acid and 3g of potassium iodide,and titrate the liberated iodine with 0.1Nsodium thiosulfate VS,adding about 2g of potassium thiocyanate and 3mLof starch TSas the endpoint is approached.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nsodium thiosulfate is equivalent to 15.96mg of CuSO4.
Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 553
Pharmacopeial Forum:Volume No.29(5)Page 1447
Phone Number:1-301-816-8394