Substance soluble in ethanol max 0.2%Substances soluble in HCl max 1.0%Chloride(Cl) max 0.05%Sulphate(SO4) max 0.01%Heavy metals(as Pb) max 0.005%Iron(Fe) max 0.015%Loss on drying(120oC) max 8.0%pH Value 6.5 to 7.5Methylene blue value min 240.0