Alanine
C3H7NO2 89.09
l-Alanine
[56-41-7].
(al' a neen).
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C3H7NO2 89.09
l-Alanine
[56-41-7].DEFINITION
Alanine contains NLT 98.5% and NMT 101.5% of C3H7NO2, as l-alanine, calculated on the dried basis.
IDENTIFICATION
ASSAY
• Procedure
Sample:
80 mg of Alanine
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 in 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 0.1 N perchloric acid VS. Calculate the percentage of C3H7NO2 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: 89.09 mg/mEq |
| W | = | = weight of the Sample (mg) |
Acceptance criteria:
98.5%–101.5% on the dried basis
IMPURITIES
Inorganic Impurities
• Residue on Ignition 281:
NMT 0.15%
281:
NMT 0.15%
• 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-Alanine RS. [Note—This solution has a concentration equivalent to 0.5% of that of the Sample solution. ]
System suitability solution:
0.4 mg/mL each of USP l-Alanine RS and USP Glycine RS
Sample solution:
10 mg/mL of Alanine
Spray reagent:
2 mg/mL of ninhydrin in a mixture of butyl alcohol and 2 N acetic acid (95:5)
Developing solvent system:
Butyl alcohol, glacial acetic acid, and water (60:20:20)
Application volume:
5 µL
Analysis
Samples:
Standard solution, System suitability solution, and Sample solution
Proceed as directed for Chromatography 621, Thin-Layer Chromatography. After air-drying the plate, repeat the development process. After air-drying a second time, spray with Spray reagent, and heat to 100
–105 for 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. After air-drying the plate, repeat the development process. After air-drying a second time, spray with Spray reagent, and heat to 100–105 for 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 of the Sample solution is not larger or more intense than the principal spot of the Standard solution, NMT 0.5%
Total impurities:
NMT 2.0%
SPECIFIC TESTS
• Optical Rotation, Specific Rotation 781S:
+13.7 to +15.1
781S:
+13.7 to +15.1
Sample solution:
100 mg/mL in 6 N hydrochloric acid
• pH 791:
5.5–7.0, in a solution (1 in 20)
791:
5.5–7.0, in a solution (1 in 20)
• Loss on Drying 731:
Dry a sample at 105 for 3 h: it loses NMT 0.2% of its weight.
731:
Dry a sample at 105 for 3 h: it loses NMT 0.2% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight containers, and store at controlled room temperature.
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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 2081
Pharmacopeial Forum: Volume No. 27(5) Page 2973