Ammonium Phosphate
(NH4)2HPO4 132.06
Phosphoric acid, diammonium salt;
Diammonium phosphate
[7783-28-0].
(a moe' nee um fos' fate).
(NH4)2HPO4 132.06
Phosphoric acid, diammonium salt;
Diammonium phosphate
[7783-28-0].DEFINITION
Ammonium Phosphate contains NLT 96.0% and NMT 102.0% of (NH4)2HPO4.
IDENTIFICATION
• A. Identification Tests—General, Ammonium 
191
:
A solution (1 in 20) meets the requirements.
191:
A solution (1 in 20) meets the requirements.
• B. Identification Tests—General, Phosphate 191:
A solution (1 in 20) meets the requirements.
191:
A solution (1 in 20) meets the requirements.
ASSAY
• Procedure
Sample:
600 mg of Ammonium Phosphate
Titrimetric system
(See Titrimetry 541.)
541.)
Mode:
Direct titration
Titrant:
0.1 N sulfuric acid VS
Endpoint detection:
potentiometric
Analysis:
Dissolve the Sample in 40 mL of water, and titrate with 0.1 N sulfuric acid VS to a pH of 4.6. Each mL of 0.1 N sulfuric acid is equivalent to 13.21 mg of (NH4)2HPO4.
Acceptance criteria:
96.0%–102.0%
IMPURITIES
• Chloride and Sulfate, 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%).
• Chloride and Sulfate, 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:
NMT 3 ppm
211:
NMT 3 ppm
• Heavy Metals 231
231
Test preparation:
Dissolve 2.0 g in 25 mL of water.
Acceptance criteria:
NMT 10 ppm
SPECIFIC TESTS
• pH 791:
7.6–8.2, in a solution (1 in 100)
791:
7.6–8.2, in a solution (1 in 100)
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight containers.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Robert H. Lafaver, M.S.
Scientific Liaison 1-301-816-8335 |
(EXC2010) Monographs - Excipients |
USP35–NF30 Page 1699