Ammonium Phosphate
(NH4)2HPO4
132.06
132.06Phosphoric 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).
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%).
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%).
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.
211:
3 ppm.
Heavy metals 231—
Dissolve 2.0 g in 25 mL of water: the limit is 0.001%.
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.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
| Monograph | Robert H. Lafaver, B.A.
Scientist 1-301-816-8335 |
(EM105) Excipient Monographs 1 |
USP32–NF27 Page 1165