11/6/2020 USP-NF Strong Ammonia Solution
Printed on: Fri Nov 06 2020, 15:39:01 pm
Printed by: Shruti Kharidia
O cial Status: Currently O cial on 06-Nov-2020
O cial Date: O cial as of 1-Jan-2018
Document Type: NF
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© 2020 USPC
Strong Ammonia Solution
NH3 17.03
Ammonia [7664-41-7].
DEFINITION
Strong Ammonia Solution is a solution of NH3, containing NLT 27.0% and NMT 31.0% (w/w) of NH3. On exposure to air, it loses
ammonia rapidly.
[CAUTION—Use care in handling Strong Ammonia Solution because of the caustic nature of the Solution and the irritating properties of its
vapor. Cool the container well before opening, and cover the closure with a cloth or similar material while opening. Do not taste Strong
Ammonia Solution, and avoid inhalation of its vapor.]
IDENTIFICATION
• A.
Analysis: Hold a glass rod moistened with hydrochloric acid near the surface of the Solution.
Acceptance criteria: Dense, white fumes are produced.
ASSAY
• PROCEDURE
Sample: Transfer quickly a portion of Strong Ammonia Solution to a stoppered, thick-walled container (a pressure bottle is suitable) to
L
obtain a column height of about 20 cm, insert the stopper, and cool the container and contents to 10° or lower. Accurately weigh a
glass-stoppered, 125-mL conical ask containing 35.0 mL of 1 N sulfuric acid VS. Insert a graduated 10-mL measuring pipet into the
cooled solution, allow the liquid to rise in the pipet without vacuum, remove the pipet, wipe off adhering liquid, and discard the rst
IA
mL of the solution permitted to run from the pipet. Hold the pipet just above the surface of the 1 N sulfuric acid VS in the conical
ask, and transfer about 2 mL of the solution into the ask. Insert the stopper, and again weigh to obtain the weight of the portion
taken of the Sample.
Titrimetric system
IC
(See Titrimetry 〈541〉.)
Mode: Residual titration
Titrant: 1 N sulfuric acid VS
Back titrant: 1 N sodium hydroxide VS
Blank: Proceed as directed for the Sample, omitting the Strong Ammonia Solution
FF
Endpoint detection: Colorimetric
Analysis
Calculate the percentage of NH3 in the portion of the Sample taken:
Result = [(B − V) × N × F × 100]/W
O
B = 1 N sodium hydroxide VS consumed by the Blank (mL)
V = 1 N sodium hydroxide VS consumed by the Sample (mL)
N = actual normality of the Back titrant (mEq/mL)
F = equivalency factor, 17.03 mg/mEq
W = weight of the Sample (mg)
Titrate the excess acid with 1 N sodium hydroxide VS, using methyl red TS as the indicator. Perform a blank determination. Each mL
of 1 N sulfuric acid is equivalent to 17.03 mg of NH3.
Acceptance criteria: 27.0%–31.0%
IMPURITIES
• LIMIT OF NONVOLATILE RESIDUE
Sample: 10 mL
Analysis: Evaporate the Sample in a tared platinum or porcelain dish to dryness, and dry at 105° for 1 h.
Acceptance criteria: NMT 5 mg of residue remains (0.05%).
• READILY OXIDIZABLE SUBSTANCES
Sample solution: 4 mL of Strong Ammonia Solution
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11/6/2020 USP-NF Strong Ammonia Solution
Analysis: Mix the Sample solution with 6 mL of water, and add a slight excess of 2 N sulfuric acid and 0.10 mL of 0.1 N potassium
permanganate.
Acceptance criteria: The pink color does not completely disappear within 10 min.
ADDITIONAL REQUIREMENTS
• PACKAGING AND STORAGE: Preserve in tight containers, at a temperature not above 25°.
Auxiliary Information- Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
STRONG AMMONIA SOLUTION Galina Holloway SE2020 Simple Excipients
Senior Scienti c Liaison
Chromatographic Database Information: Chromatographic Database
Page Information:
USP43-NF38 - 5616
USP42-NF37 - 5569
USP41-NF36 - 5197
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