|
Item
|
Quality Index
|
|
|
Food Grade
|
Industry Grade
|
|
|
Purity ( As Na2S2O5)
|
98.0% min
|
96.0% min
|
|
Sulfur Dioxide( SO2)
|
65.0% min
|
65.0% min
|
|
Arsenic ( As )
|
0.0002% max
|
-
|
|
Heavy metals ( As Pb )
|
0.0005% max
|
-
|
|
Selenium (Se )
|
0.0005% max
|
-
|
|
Iron (Fe)
|
0.001% max
|
0.002% max
|
|
Water insoluble
|
0.02% max
|
0.05% max
|
|
PH value :
|
4.0-4.8
|
4.0-4.8
|
|
Remark :
|
Conformed with FCC V and E 223 Standard
|
|
Specification for Pharmaceutical Grade and Photo Grade
|
Item
|
Quality Index
|
|
|
Pharmaceutical Grade
|
Photo Grade
|
|
|
Purity ( As Na2S2O5)
|
98.0% min
|
98.0% min
|
|
Sulfur Dioxide( SO2)
|
65.0% min
|
65.0% min
|
|
Thiosulphate ( As S2O3) :
|
0.05 % max
|
0.05% max
|
|
Chloride ( As CL-) :
|
30 ppm max
|
50ppm max
|
|
Arsenic ( As ) :
|
1ppm max
|
1ppm max
|
|
Lead ( Pb ) :
|
1 ppm max
|
2ppm max
|
|
Copper (Cu) :
|
1 ppm max
|
1ppm max
|
|
Iron (Fe ) :
|
5 ppm max
|
5ppm max
|
|
Mercury (Hg) :
|
0.1ppm max
|
1ppm max
|
|
Chromium (Cr) :
|
1 ppm max
|
-
|
|
Selenium (Se ) :
|
1 ppm max
|
5ppm max
|
|
Zinc (Zn)
|
1 ppm max
|
1ppm max
|
|
Cadmium (Cd )
|
1ppm max
|
-
|
|
Nickel (Ni)
|
1ppm max
|
-
|
|
Na2SO3 + Na2SO4
|
1.5% max
|
-
|
|
PH value :
|
4.0-4.8
|
4.0-4.8
|
|
Remark :
|
Conformed with USP standard
|
|