L-Cysteine：
| General Information |
| Products name:L-Cysteine |
| CAS NO :52-90-3 |
| EINECS NO: 200-158-2 |
| Molecular formula: C3H7NO2S |
| Molecular weight: 121.16 |
| Appearance: twin monoclinic or orthogonal crystallization, melting point 178 ℃, (a) + 26.5 (mol/L HCL), imine tastes, in neutral or slightly alkaline solution easy oxidation by air into cystine, acidic environment is stable. |
| Solubility:soluble in water, ethanol, not soluble in ethanol, propanol, ethyl acetate, stupid, carbon disulfide, carbon tetrachloride. |
| USES: used in the treatment of skin conditions such as eczema, urticaria, freckles, the series products are widely used in medicine, food and cosmetics industries. |
| Standard: AJI92 |
| BASIC ANALYSIS | ||
| Item of Analysis | Specification | Results |
| Assay | 98.0%～101.0% | 98.5% |
| Organoleptic | ||
| Appearance | White powder | Conforms |
| Odor | Characteristic | Conforms |
| Taste | Characteristic | Conforms |
| Physical Characteristics | ||
| Specific optical rotation[a]D 20+ | + 8.3°- +9.5° | +8.7° |
| State of solution (Transmittance) | ≥95.0% | 98.5% |
| Loss on drying | ≤0.50% | 0.32% |
| Residue on ignition | ≤0.10% | 0.06% |
| pH value | 4.5 ～ 5.5 | 4.8 |
| Heavy metals | ||
| Heavy metals(Pb) | ≤10PPM | 3PPM |
| Chloride (Cl) | ≤0.04% | 0.030% |
| Arsenic (As2O3) | ≤1PPM | 0.1PPM |
| Iron (Fe) | ≤10PPM | 4PPM |
| Ammonium (NH4) | ≤0.02% | 0.010% |
| Sulfate (SO4) | ≤0.020% | 0.010% |
| Other amino acids | Chromatographically | Qualified |
