Sodium Metabisulphate (food grade)97% Molecular formula:Na2S2O5 CAS#:7681-57-4 HS Code:28311000 Appearance:White powder Qualities are conformed:HG/T2935-2006 Items Unit Specification Purity %min 96 AS (ppm)max 5 Fe (ppm)max 50 Pb (ppm)max 10 Cd (ppm)max 10 PH 4-5 Water insolubles %max 0.05 Packing Net 25Kgs woven bags with inner liner. Storage Sealed in cool and dry place.