Testing Item Citric Acid Anhydrous Citric Acid Monohydrate Assay/% 99.5~100.5 99.5~101.5 Water/% 0.5 7.5~9 Sulphated Ash (Residue On Ignition)/% 0.05 0.05 Sulphate/% 0.01 0.015 Oxalate/% â?¤0.01 0.01 Calcium(Ca)/% 0.02 0.02 Iron(Fe)/% 0.0005 0.0005 Chloride(Cl)/% 0.005 0.005 Readily Carbureted Substances/% K1.0 K .0 Arsenic(As)/% 0.0001 0.0001 Heavy metal(Pb)/% 0.00005 0.00005