Phosphoric acid, diammonium salt.
Diammonium phosphate [7783-28-0].
» Ammonium Phosphate contains not less than 96.0 percent and not more than 102.0 percent of (NH4)2HPO4.
Packaging and storage Preserve in tight containers.
pH 791: between 7.6 and 8.2, in a solution (1 in 100).
Chloride 221 A 1.0-g portion shows no more chloride than corresponds to 0.40 mL of 0.020 N hydrochloric acid (0.03%).
Sulfate 221 A 0.20-g portion shows no more sulfate than corresponds to 0.30 mL of 0.020 N sulfuric acid (0.15%).
Arsenic, Method I 211: 3 ppm.
Heavy metals 231 Dissolve 2.0 g in 25 mL of water: the limit is 0.001%.
Assay Dissolve about 600 mg of Ammonium Phosphate, accurately weighed, in 40 mL of water, and titrate with 0.1 N sulfuric acid VS to a pH of 4.6, determined potentiometrically. Each mL of 0.1 N sulfuric acid is equivalent to 13.21 mg of (NH4)2HPO4.