|
Testing Item |
Standard |
Result |
|
Assay |
99.0%-100.5% |
99.72% |
|
Appearance |
White or almost White crystals Crystalline Powder |
pass |
|
Solubity |
Easily soluble in water |
pass |
|
Identification |
Positive Reaction |
Positive |
|
Melting Point |
About 190ºC |
190.6 ºC |
|
Copper |
≤5ppm |
<5ppm |
|
Heavy Metals |
≤10ppm |
<10ppm |
|
Mercury |
≤0.1mg/kg |
<0.1mg/kg |
|
Lead |
≤2mg/kg |
<2mg/kg |
|
Arsenic |
≤3ppm |
<3ppm |
|
Oxalic Acid |
≤0.2% |
<0.2% |
|
Iron |
≤2ppm |
<2ppm |
|
Cadmium(Cd) |
<1mg/kg |
<1mg/kg |
|
Impurity E |
≤0.2% |
<0.2% |
|
Loss on Drying |
≤0.4% |
<0.4% |
|
Sulphate Ash(Residue On Ignition) |
≤0.1% |
<0.1% |
|
Specific Optical Rotation |
+20.5°-+21.5° |
21.08° |
1.Cosmetics
1) L-Vitamin C inhibits tyrosinase and reduces melanin, and diminishes the formed spots to inhibit melanin formation.