ITEM STANDARD Na5p3o10 % >= 95.0 p2o5 % >= 57.0 water insoluble % <= 0.05 F % <= 0.003 As % <= 0.00013 Heavy metals (Pb) % <= 0.001 chloride (Cl) % <= 0.025 sulphate (so4) % <= 0.4 whiteness % >= 85 ph(1% aqueous solution) 9.5-10.0