Character                 white or almost white crystalline powder          
Identification                     positive reaction                       
Melting point                     about 190℃                            
PH                                     2.1-2.6                              
Clarity of solutinon                 clear                                 
Colour of solution                  ≤BY7                               
Copper                                 ≤5ppm                               
Heavy metal                        ≤10ppm                              
Lead                                    ≤2ppm                               
Iron                                    ≤2ppm                               
Arxenic                              ≤3ppm                                
Oxalic acid                          ≤0.2%                                
Sulphate ash
(residue on ignition)                0.1%                                
Specific opticalrotation          +20.5+21.5°                          
Assay                            99%-100.5%                           
Organic volatile impurities          pass                                  
Residual solvents                methanol NMT 3000ppm