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L-Cysteine (Free Base)
| Tests | Specifications |
| Assay | 98.0 ~ 102.0% |
| Specific Rotation [a]20D | +7.0' ~ +9.0' |
| Color & Clarity of Solution | Colorless and clear |
| Loss on Drying | Less than 0.5% |
| Residue on Ignition
(as sulfate) |
Less than 0.1% |
| Arsenic (as As2 O3) | Less than 1 ppm |
| Heavy Metals (as Pb) | Less than 10 ppm |
| Iron (Fe) | Less than 10 ppm |
| Other Amino Acids | Chromatographically not detectable |
| Sulfate (SO4) | Less than 0.028% |
| Ammonium (NH4) | Less than 0.02% |
| Chloride (Cl) | Less than 0.05% |