CAS number： 63-68-3
Molecular formula： C5H11NO2S
molecular weight： 149.21
Chemical structure：
| Product | L－Methionine | |
| Shelf Life | 3 years | |
| Reference standard | USP 32 | |
| Item | Standard | Conclusion of analysis |
| Description | white crystals or crystalline powder | white crystalline powder |
| Identification | meets the requirements | meet the requirements |
| Specific rotation | +22.4°～+24.7° | +23.9° |
| pH | 5.6～6.1 | 5.8 |
| Loss on drying | not more than 0.3% | 0.12% |
| Residue on ignition | not more than 0.4% | 0.08% |
| Chloride | not more than 0.05% | less than 0.05% |
| Sulfate | not more than 0.03% | less than 0.03% |
| Iron | not more than 0.003% | less than 0.003% |
| Heavy metals | not more than 0.0015% | less than 0.0015% |
| Chromatographic purity | individual impurity≤0.5% | meet the requirements |
| Total impurities≤2.0% | meet the requirements | |
| Organic volatile impurities | meet the requirements | meet the requirements |
| Assay | 98.5%～101.5% | |
