(gloo' ta meen).
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C5H10N2O3 146.14
2-Aminoglutaramic acid     [56-85-9].
Glutamine contains NLT 98.5% and NMT 101.5% of l-glutamine (C5H10N2O3), calculated on the dried basis.
•  Procedure
Sample:  150 mg of Glutamine
Blank:  Mix 3 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 3 mL of formic acid and 50 mL of glacial acetic acid, and titrate with the Titrant. Perform a Blank determination.
Calculate the percentage of glutamine (C5H10N2O3) 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, 146.1 mg/mEq
W== Sample weight (mg)
Acceptance criteria:  98.5%–101.5% on the dried basis
•  Residue on Ignition 281: NMT 0.3%
•  Chloride and Sulfate, Chloride 221
Standard solution:  0.50 mL of 0.020 N hydrochloric acid
Sample:  0.7 g of Glutamine
Acceptance criteria:  NMT 0.05%
•  Chloride and Sulfate, Sulfate 221
Standard solution:  0.25 mL of 0.020 N sulfuric acid
Sample:  0.8 g of Glutamine
Acceptance criteria:  NMT 0.03%
•  Iron 241: NMT 30 ppm
•  Heavy Metals, Method I 231: NMT 15 ppm
•  Related Compounds
Standard solution:  0.05 mg/mL of USP Glutamine RS in water
Sample solution:  10 mg/mL of Glutamine 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)
Analysis:  Dry the plate at 80 for 30 min. Spray the plate with Spray reagent, heat at 80 for 10 min, and examine under white light.
Acceptance criteria:  No secondary spot of the Sample solution is larger or more intense than the principal spot of the Standard solution (NMT 0.5%).
•  Optical Rotation, Specific Rotation 781S
Sample solution:  40 mg/mL in water. Warm at 40 to dissolve.
Analysis:  Proceed as directed in the chapter, except measure at 20.
Acceptance criteria:  +6.3 to +7.3
•  Loss on Drying 731: Dry a sample at 105 for 3 h: it loses NMT 0.3% of its weight.
•  Packaging and Storage: Preserve in well-closed containers, and store at controlled room temperature.
•  USP Reference Standards 11
USP Glutamine 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 3346