Glutamic Acid
(gloo tam' ik as' id).
Click to View Image

C5H9NO4 147.13
l-Glutamic acid;    
S-2-Aminopentanedioic acid     [56-86-0].
Glutamic Acid contains NLT 98.5% and NMT 101.5% of l-glutamic acid (C5H9NO4), calculated on the dried basis.
•  Procedure
Sample:   140 mg of Glutamic Acid
Blank:  Mix 6 mL of formic acid and 50 mL of glacial acetic acid.
Titrimetric system 
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
VS== volume of Titrant consumed by the Sample (mL)
VB== volume of Titrant consumed by the Blank (mL)
N== actual normality of the Titrant (mEq/mL)
F== equivalency factor, 147.1 mg/mEq
W== Sample weight (mg)
Acceptance criteria:  98.5%–101.5% on the dried basis
•  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%
•  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.
•  Packaging and Storage: Preserve in well-closed containers, and store at controlled room temperature.
•  USP Reference Standards 11
USP Aspartic Acid RS Click to View Structure
USP Glutamic Acid RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Huy T. Dinh, M.S.
Scientific Liaison
(DS2010) Monographs - Dietary Supplements
Reference Standards RS Technical Services
USP35–NF30 Page 1342
Pharmacopeial Forum: Volume No. 34(4) Page 997