【CAS】60-18-4
【Molecular formula】:C9H11NO3
【Molecular weight】: 181.19
【Properties】Colorless or white crystals, or white crystalline powder (from starch or rice), or brownish yellow (from molasses); almost tasteless, odorless, with special taste and sour taste. When heated to 160°C, it melts and separates out water molecules, and decomposes at 224~225°C. The aqueous solution is acidic, and the pH value of the saturated aqueous solution is about 3.2. Insoluble in water (0.72g/100ml, 20℃; 6.66g/100ml, 80℃).
| L-Tyrosine | USA index | AJI92 | Europe index | First grade |
| Assay | 98.5-101.5% | 99.0-100.5% | 99.0-101.0% | ≥99.0% |
| PH | / | 5.0-6.5 | / | 5.0-6.5 |
| Specific rotation[a]D20 | / | -11.3°--12.1° | -11.0°--12.3° | -11.3°--12.1° |
| Specific rotation[a]D25 | -9.8°--11.2° | / | / | / |
| Transmittance(T430) | / | ≥95.0% | clear & colorless | ≥95.0% |
| Chloride(Cl) | ≤0.04% | ≤0.02% | ≤0.02% | ≤0.02% |
| Ammonium(NH4) | / | ≤0.02% | ≤0.02% | ≤0.02% |
| Sulfate(SO4) | ≤0.04% | ≤0.02% | ≤0.03% | ≤0.02% |
| Iron(Fe) | ≤30PPM | ≤10PPM | ≤10PPM | ≤10PPM |
| Heavy metals(Pb) | ≤15PPM | ≤10PPM | ≤10PPM | ≤10PPM |
| Arsenic | / | ≤1PPM | / | ≤1PPM |
| Other amino acids | individual impurities≤0.5% total impurities≤2.0% | conform | / | ≤0.40% |
| Ninhydrin-positive substances | / | / | conform | / |
| Loss on drying | ≤0.3% | ≤0.20% | ≤0.50% | ≤0.20% |
| Residue on ignition | ≤0.40% | ≤0.10% | ≤0.10% | ≤0.10% |
| Organic volatile impurities | / | / | / | / |
| Endotoxin | / | / | / | <0.25EU/ml |