Item

Quality Index

Food Grade

Industry Grade

Purity ( As Na2S2O5)

98.0% min

97.0% 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