Arginine
C6H14N4O2 174.20
l-Arginine
[74-79-3].
(ar' ji neen).
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C6H14N4O2 174.20
l-Arginine
[74-79-3].DEFINITION
Arginine contains NLT 98.5% and NMT 101.5% of C6H14N4O2, as l-arginine, calculated on the dried basis.
IDENTIFICATION
ASSAY
• Procedure
Sample:
80 mg of Arginine
Titrimetric system
(See Titrimetry 
541
.)
541.)
Mode:
Direct titration
Titrant:
0.1 N perchloric acid VS
Endpoint detection:
Potentiometric
Blank:
3 mL of formic acid and 50 mL of glacial acetic acid
Analysis:
Dissolve the Sample in a mixture of 3 mL of formic acid and 50 mL of glacial acetic acid, and titrate with Titrant. Calculate the percentage of C6H14N4O2 in the portion taken:
Result = [(V 
B) × N × F × 100]/W
B) × N × F × 100]/W| V | = | = Sample titrant volume (mL) |
| B | = | = Blank titrant volume (mL) |
| N | = | = titrant normality (mEq/mL) |
| F | = | = equivalency factor: 87.10 mg/mEq |
| W | = | = weight of Sample (mg) |
Acceptance criteria:
98.5%–101.5% on the dried basis
IMPURITIES
Inorganic Impurities
• Residue on Ignition 281:
NMT 0.3%
281:
NMT 0.3%
• Chloride and Sulfate, Chloride 221:
A 1.0-g portion shows no more chloride than corresponds to 0.70 mL of 0.020 N hydrochloric acid (0.05%).
221:
A 1.0-g portion shows no more chloride than corresponds to 0.70 mL of 0.020 N hydrochloric acid (0.05%).
• Chloride and Sulfate, Sulfate 221:
A 1.0-g portion shows no more sulfate than corresponds to 0.30 mL of 0.020 N sulfuric acid (0.03%).
221:
A 1.0-g portion shows no more sulfate than corresponds to 0.30 mL of 0.020 N sulfuric acid (0.03%).
• Iron 241:
NMT 30 ppm
241:
NMT 30 ppm
• Heavy Metals, Method I 231:
NMT 15 ppm
231:
NMT 15 ppm
Organic Impurities
• Procedure
Adsorbent:
0.25-mm layer of chromatographic silica gel mixture
Standard solution:
0.05 mg/mL of USP l-Arginine RS in 0.1 N hydrochloric acid. [Note—This solution has a concentration equivalent to 0.5% of that of the Sample solution. ]
Sample solution:
10 mg/mL of Arginine in 2 N hydrochloric acid
System suitability solution:
0.4 mg/mL each of USP l-Arginine RS and USP l-Lysine Hydrochloride RS in 0.1 N hydrochloric acid
Spray reagent:
2 mg/mL of ninhydrin in a mixture of butyl alcohol and 2 N acetic acid (95:5)
Application volume:
5 µL
Developing solvent system:
Isopropyl alcohol and ammonium hydroxide (7:3)
Analysis
Samples:
Standard solution, Sample solution, and System suitability solution
Proceed as directed under Chromatography 621, Thin-Layer Chromatography. Dry the plate between 100
and 105 until the ammonia disappears completely. Spray with Spray reagent, and heat between 100 and 105 for about 15 min. Examine the plate under white light. The chromatogram obtained from the System suitability solution exhibits two clearly separated spots.
621, Thin-Layer Chromatography. Dry the plate between 100 and 105 until the ammonia disappears completely. Spray with Spray reagent, and heat between 100 and 105 for about 15 min. Examine the plate under white light. The chromatogram obtained from the System suitability solution exhibits two clearly separated spots.
Acceptance criteria
Individual impurities:
Any secondary spot from the Sample solution is not larger or more intense than the principal spot from the Standard solution, NMT 0.5%
Total impurities:
NMT 2.0%
SPECIFIC TESTS
• Optical Rotation, Specific Rotation 781S:
+26.3 to +27.7
781S:
+26.3 to +27.7
Sample solution:
80 mg/mL in 6 N hydrochloric acid
• Loss on Drying 731:
Dry a sample at 105 for 3 h: it loses NMT 0.5% of its weight.
731:
Dry a sample at 105 for 3 h: it loses NMT 0.5% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
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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 1-301-816-8594 |
(DS2010) Monographs - Dietary Supplements |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2238