Glutamic Acid
(gloo tam' ik as' id).
DEFINITION
Glutamic Acid contains NLT 98.5% and NMT 101.5% of l-glutamic acid (C5H9NO4), calculated on the dried basis.
IDENTIFICATION
ASSAY
• Procedure
Sample:
140 mg of Glutamic Acid
Blank:
Mix 6 mL of formic acid and 50 mL of glacial acetic acid.
Titrimetric system
(See Titrimetry 541.)
Mode:
Direct titration
Titrant:
0.1 N perchloric acid VS
Endpoint detection:
Potentiometric
Analysis:
Dissolve the Sample in 6 mL of formic acid and 50 mL of glacial acetic acid, and titrate with the Titrant. Perform the Blank determination.
Calculate the percentage of glutamic acid (C5H9NO4) in the Sample taken:
Result = {[(VS VB) × N × F]/W} × 100
Acceptance criteria:
98.5%101.5% on the dried basis
IMPURITIES
• Residue on Ignition 281:
NMT 0.1%
• Chloride and Sulfate, Chloride 221
Standard solution:
0.40 mL of 0.010 N hydrochloric acid
Sample:
0.7 g of Glutamic Acid
Acceptance criteria:
NMT 0.02%
• Chloride and Sulfate, Sulfate 221
Standard solution:
0.25 mL of 0.020 N sulfuric acid
Sample:
1.2 g of Glutamic Acid
Acceptance criteria:
NMT 0.02%
• Iron 241:
NMT 10 µg/g
• Heavy Metals, Method 1 231:
NMT 10 µg/g
• Related Compounds
Standard solution:
0.05 mg/mL of USP Glutamic Acid RS in water
Sample solution:
10 mg/mL in a solution of ammonia TS and water (1:1)
System suitability solution:
0.4 mg/mL each of USP Aspartic Acid RS and USP Glutamic Acid RS in water
Chromatographic system
Mode:
TLC
Adsorbent:
0.25-mm layer of chromatographic silica gel mixture
Application volume:
5 µL
Developing solvent system:
Butyl alcohol, glacial acetic acid, and water (3:1:1)
Spray reagent:
2 mg/mL of ninhydrin in a mixture of butyl alcohol and 2 N acetic acid (95:5)
System suitability
Suitability requirements:
The chromatogram from the System suitability solution exhibits two clearly separated spots.
Analysis:
After air-drying the plate, repeat the development process. After air-drying a second time, spray with Spray reagent, and heat between 100 and 105 for about 15 min. Examine the plate under white light.
Acceptance criteria:
Any secondary spot of the Sample solution is not larger or more intense than the principal spot of the Standard solution.
Individual impurities:
NMT 0.5%
Total impurities:
NMT 2.0%
SPECIFIC TESTS
• Optical Rotation, Specific Rotation 781S
Sample solution:
100 mg/mL in 2 N hydrochloric acid
Analysis:
Proceed as directed in the chapter, except measure at 20.
Acceptance criteria:
+31.5 to +32.5
• Loss on Drying 731:
Dry a sample at 105 for 3 h: it loses NMT 0.1% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers, and store at controlled room temperature.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 1342
Pharmacopeial Forum: Volume No. 34(4) Page 997
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