CAS NO: 56-89-3
Specification: EP5
| Product Name | L-Cystine |
| Quality Standard | EP5 |
| Testing Items | Critrion |
| Appearance | A white, crystalline powder |
| State of solution | Clear and not more intensely coloured than reference solution Y7 |
| Specific rotation | -218~-224° |
| Ninhydrin-positive substances | Not more intense than the spot in the chromatogram obtained with reference solution (0.2%) |
| Chloride(Cl) | ≤200ppm |
| Sulphates | ≤300ppm |
| Ammonium(NH4) | ≤200ppm |
| Iron(Fe) | ≤10ppm |
| Heavy metals(Pb) | ≤10ppm |
| Loss on drying | ≤0.50% |
| Sulphated ash | ≤0.10% |
| Assay | 98.5~101.0% |