Appearance                                                       white or yellowish-white, hygroscopic powder or flakes    

Solubility:                                                          Free soluble in water,in ethanol ( 96 per cent ) and in methanol,

very slightly soluble in acetone

Identification:                                                     A.B.C.D.E.(EP5)                            

Appearance of solution                                       B6, BY6 or R6 min                              

PH (10% solution in water)                                  3.0-5.0                 

K-value                                                              12.8-17.3       

Aldehyde:                                                          0.05%max                   

Peroxide compounds:                                         400ppm max               

Hydrazine:                                                         1ppm max                  

Impurity A (Vinylpyrrolidone)                              10ppm max                 

Impurity B (2-pyrrolidone)                                  3.0%max             

Heavy metal:                                                     10ppm max                        

Lead                                                                 10ppm max                                      

Water (Karl Fischer):                                          5.0%max.            

Sulphate ashes                                                  0.1%max                                                       

Nitrogen:                                                           11.5-12.8%           

Microbe Limit                                                     cf.EP5