ITEM TESTED               STANDARD                        RESULT

Purity(Na2S2O5)             96.5% min                             97%

Iron(Fe)                           0.005% min                          <0.003%

Aresentic(As)                  1 ppm  max                           <1 ppm

Water insoluble               0.05% max                              0.01%

PH value                           4.0-4.6                                    4.4