Lysine Acetate
(lye' seen as' e tate).
Click to View Image

C6H14N2O2·C2H4O2 206.24
l-Lysine monoacetate     [57282-49-2].
Lysine Acetate contains NLT 98.0% and NMT 102.0% of l-lysine acetate (C6H14N2O2·C2H4O2), calculated on the dried basis.
•  Procedure
Sample:  100 mg of Lysine Acetate
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. Titrate with the Titrant. Perform the Blank determination.
Calculate the percentage of lysine acetate (C6H14N2O2·C2H4O2) in the Sample taken:
Result = {[(VS VB) × N × F]/W} × 100
VS== Titrant volume consumed by the Sample (mL)
VB== Titrant volume consumed by the Blank (mL)
N== actual normality of the Titrant (mEq/mL)
F== equivalency factor, 103.1 mg/mEq
W== Sample weight (mg)
Acceptance criteria:  98.0%–102.0% on the dried basis
•  Residue on Ignition 281: NMT 0.4%
•  Chloride and Sulfate, Chloride 221
Standard solution:  0.50 mL of 0.020 N hydrochloric acid
Sample:  0.73 g of Lysine Acetate
Acceptance criteria:  NMT 0.05%
•  Chloride and Sulfate, Sulfate 221
Standard solution:  0.10 mL of 0.020 N sulfuric acid
Sample:  0.33 g of Lysine Acetate
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 l-Lysine Acetate RS in water
[Note—This solution has a concentration equivalent to 0.5% of that of the Sample solution. ]
Sample solution:  10 mg/mL of Lysine Acetate in water
System suitability solution:  0.4 mg/mL each of USP l-Lysine Acetate RS and USP Arginine Hydrochloride RS
Chromatographic system 
Mode:  TLC
Adsorbent:  0.25-mm layer of chromatographic silica gel mixture
Application volume:  5 µL
Developing solvent system:  Isopropyl alcohol and ammonium hydroxide (7:3)
Spray reagent:  0.2 g of ninhydrin in a mixture of butyl alcohol and 2 N acetic acid (95:5)
System suitability 
Suitability requirements:  The chromatogram of the System suitability solution exhibits two clearly separated spots.
Samples:  Standard solution, System suitability solution, and Sample solution
Dry the plate between 100 and 105 until the ammonia completely disappears. Spray with Spray reagent, and heat between 100 and 105 for 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 water
Acceptance criteria:  +8.4 to +9.9
•  Loss on Drying 731: Dry a sample at 80 for 3 h: it loses NMT 0.2% of its weight.
•  Packaging and Storage: Preserve in well-closed containers.
•  USP Reference Standards 11
USP Arginine Hydrochloride RS Click to View Structure
USP l-Lysine Acetate 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 3732