| Item |
Quality Index
|
|
|
Photo Grade
|
Pharmaceutical Grade
|
|
|
Purity ( As Na2SO3)
|
98.0% min
|
98.0% min
|
|
Sodium sulphate ( SO4 )
|
1.0% max
|
1.0% max
|
|
Chlorides ( As CL - )
|
0.05% max
|
0.05% max
|
|
Arsenic ( As )
|
0.0002% max
|
2ppm max
|
|
Lead ( As Pb)
|
0.0005% max
|
2ppm max
|
|
Iron (Fe)
|
0.001% max
|
5ppm max
|
|
Selenium ( Se)
|
0.0001% max
|
1ppm max
|
|
Zinc ( Zn)
|
0.0001% max
|
1ppm max
|
|
Copper ( Cu )
|
0.0001% max
|
0.1ppm max
|
|
Mercury ( Hg)
|
0.0001% max
|
0.1 ppm max
|
