Item Standard Appearance White crystals with lumps Specific rotation[α]D/20 (C=2 in H2O) +10.8°to +12.3° Melting Point (ºC) 160 to 163 ºC Chloride(C1) Not more than 0.02% Iron(Fe) Not more than 10ppm Heavy metals(Pb) Not more than 10ppm Arsenic(As2O3) Not more than 1ppm Loss on drying Not more than 0.20% Residue on ignition Not more than 0.10% Assay 98.0%¡«101.0%