(NH4)2HPO4 132.06

Phosphoric acid, diammonium salt.
Diammonium phosphate [7783-28-0].

Packaging and storage— Preserve in tight containers.

Identification— A solution (1 in 20) responds to the tests for Ammonium 191 and for Phosphate 191.

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%.

Residual solvents 467: meets the requirements.

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.

Expert Committee : (EM105) Excipient Monographs 1

USP29–NF24 Page 3273

Phone Number : 1-301-816-8262