... weight on drying, % 0.20 max Residue on ignition, % 0.01 max Heavy metals(Pb), ug/g 0.5 max Fe, ug/g ... 0.1 max As, ug/ ... g 0.2 max Sulphate, ug/g ... Color, APHA 5 max Conductivity, (us/cm) 5.0 max PH(10% water solution) 6.0-7.0 Ribitol, %0.1 max Glycerol, % 0.1 max Count ...