Assay(after drying) min 99.8%  Insoluble matter max 0.003%  Loss on drying at 1200C max 0.2% pH of 5% solution 6.0-9.2 Alkalinity max 0.006% Chloride and bromide(Cl) max 0.01% Iodate(IO3) max 0.0002% Nitrogen compounds(N) max 0.001% Phosphate(PO4) max 0.001% Sulphate(SO4) max 0.0025% Barium(Ba) max 0.001% Iron(Fe) max 0.0002% Lead(Pb) max 0.0002% Sodium(Na) max 0.05%