Vitamin C
Item | Standard |
Appearance | White or almost white, crystalline powder or colourless crystals |
Melting point | About 190 ºC . with decomposition |
Infrared absorption spectrum | Infrared absorption spectrum accord with the referance spectrum of ascorbic acid CRS |
PH(With 5% water solution) | 2.1-2.6 |
PH(With 2% water solution) | 2.4-2.8 |
Appearance of solution | Clarity; clear; colour: ≤ BY 7 |
Specific optical rotation | 20.5 ºC- 21.5 ºC |
Loss on drying | ≤ 0.4% |
Impurity E | ≤ 0.2% |
Related substance | Impurity C: ≤ 0.15% |
Impurity D: ≤ 0.15% | |
Unpecified impurities: ≤ 0.10% | |
Total impurities: ≤ 0.20% | |
Copper | ≤ 5.0ppm |
Iron | ≤ 2.0ppm |
Arisenic | ≤ 3.0ppm |
Lead | ≤ 2.0ppm |
Mercury | ≤ 1.0ppm |
Cadmium | ≤ 1.0ppm |
Heavy metals | ≤ 10ppm |
Sulphated ash | ≤ 0.1% |
Assay | 99.0% ~ 100.5% |