... STPP Sodium Tripolypyosphate(industrial grade)ItemStandard NoExact NoSodium Tripolypyosphate(Na5P3O10),% ≥90.092.1Phosphate(base on P2O5) ,% ≥56.557.3Insoluble ... , % ≤0.100.07PH value9.2-10.09.4Whiteness, ≥85.090Fe,% ≤0.0150.009 Sodium Tripolypyosphate(food grade)Item NoInspection ... .0250.012Qualified9Sulphate(base on SO4),% ≤0.40.32Qualified10Whiteness,≥85.087.5Qualified Sodium Tripolypyosphate STPP