Packaging and storage
Preserve in well-closed containers.
Labeling
Label it to indicate whether it is hydrous or anhydrous.
Identification
Add a few drops of a solution (1 in 20) to 5 mL of hot alkaline cupric tartrate TS: a copious red precipitate of cuprous oxide is formed.
Color of solution
Dissolve 25 g in water to make 50.0 mL of solution: the solution has no more color than a solution prepared by mixing 1.0 mL of cobaltous chloride CS, 3.0 mL of ferric chloride CS, and 2.0 mL of cupric sulfate CS with water to make 10 mL, and diluting 3 mL of this solution with water to 50 mL. Make the comparison by viewing the solutions downward in matched color-comparison tubes against a white surface.
Acidity
Dissolve 5.0 g in 50 mL of carbon dioxide-free water. Add
phenolphthalein TS, and titrate with 0.020 N sodium hydroxide to the production of a distinct pink color: not more than 0.30 mL is required for neutralization.
Water, Method III 921
Dry it at 105
for 16 hours: the hydrous form loses between 7.5% and 9.5% of its weight, and the anhydrous form loses not more than 0.5% of its weight.
Chloride 221
A 2.0-g portion shows no more chloride than corresponds to 0.50 mL of 0.020 N hydrochloric acid (0.018%).
Sulfate 221
A 2.0-g portion shows no more sulfate than corresponds to 0.50 mL of 0.020 N sulfuric acid (0.025%).
Heavy metals 231
Dissolve 4.0 g in water to make 25 mL of solution: the limit is 5 ppm.
Dextrin
Reflux 1 g of finely powdered Dextrose with 20 mL of alcohol: it dissolves completely.
Soluble starch, sulfites
To a solution of 1 g in 10 mL of water add 1 drop of iodine TS: the liquid is colored yellow.