Monosodium Glutamate
(mon'' oh soe' dee um gloo' ta mate).
DEFINITION
Monosodium Glutamate contains NLT 99.0% and NMT 100.5% of C5H8NNaO4·H2O.
IDENTIFICATION
• A.
Sample solution:
1 in 30
Analysis:
To 1 mL of the Sample solution add 1 mL of ninhydrin TS and 100 mg of sodium acetate, and heat in a boiling water bath for 10 min.
Acceptance criteria:
An intense, violet blue color is formed.
• B.
Sample solution:
1 in 10
Analysis:
To 10 mL of the Sample solution add 5.6 mL of 1 N hydrochloric acid.
Acceptance criteria:
A white, crystalline precipitate of glutamic acid is formed on standing. Precipitation is promoted by agitation. When 6 mL of 1 N hydrochloric acid is added to the turbid solution, the glutamic acid dissolves on stirring.
• C. Identification Tests—General, Sodium 
191
:
It meets the requirements of the pyroantimonate precipitate test.
191:
It meets the requirements of the pyroantimonate precipitate test.
ASSAY
• Procedure
Sample:
250 mg
Titrimetric system
(See Titrimetry 541.)
541.)
Mode:
Direct titration
Titrant:
0.1 N perchloric acid VS
Blank:
100 mL of glacial acetic acid with a few drops of water
Endpoint detection:
Potentiometric
Analysis:
Wet the Sample with a few drops of water. Dissolve in 100 mL of glacial acetic acid. Titrate with 0.1 N perchloric acid VS. Perform a blank determination.
Calculate the percentage of monosodium glutamate (C5H8NNaO4·H2O) in the Sample taken:
Result = [(V 
B) × N × F × 100]/W
B) × N × F × 100]/W
| V | = | = volume of Titrant consumed by the Sample (mL) |
| B | = | = volume of Titrant consumed by the Blank (mL) |
| N | = | = actual normality of the Titrant (mEq/mL) |
| F | = | = equivalency factor, 93.56 mg/mEq |
| W | = | = weight of the Sample (mg) |
Acceptance criteria:
99.0%–100.5%
IMPURITIES
• Chloride and Sulfate, Chloride 221:
A 280-mg portion shows no more chloride than corresponds to 1.0 mL of 0.020 N hydrochloric acid (0.25%).
221:
A 280-mg portion shows no more chloride than corresponds to 1.0 mL of 0.020 N hydrochloric acid (0.25%).
• Lead 251:
NMT 10 ppm
251:
NMT 10 ppm
• Heavy Metals, Method II 231:
NMT 20 ppm
231:
NMT 20 ppm
SPECIFIC TESTS
• Clarity and Color of Solution
Sample solution:
1.0 g in 10 mL of water
Standard solution:
To 0.2 mL of a solution of sodium chloride containing 10 µg/mL of chloride ion (Cl), add 20 mL of water, and mix. Then add 1 mL of 5 N nitric acid, 0.2 mL of dextrin solution (1 in 50), and 1 mL of silver nitrate TS, and allow to stand for 15 min.
Analysis:
Compare the Sample solution with the Standard solution (see Spectrophotometry and Light-Scattering—Visual Comparison 851).
851).
Acceptance criteria:
The Sample solution is colorless and has no more turbidity than the Standard solution.
• Optical Rotation, Specific Rotation 781S
781S
Sample solution:
100 mg/mL in 2 N hydrochloric acid
Acceptance criteria:
+24.8
to +25.3, determined at 20
to +25.3, determined at 20
• pH 791:
6.7–7.2, in a solution (1 in 20)
791:
6.7–7.2, in a solution (1 in 20)
• Loss on Drying 731:
Dry a sample at 100 for 5 h: it loses NMT 0.5% of its weight.
731:
Dry a sample at 100 for 5 h: it loses NMT 0.5% of its weight.
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 1872
Pharmacopeial Forum: Volume No. 28(3) Page 826