IP 401: Liquefied petroleum gases - detection of hydrogen sulfide- Lead acetate method

Overview:

This International  Standard specifies a method for the detection  of  hydrogen  sulfide  in  
liquefied  petroleum gases.
The  lower  limit  of  detectability  is  4 mg  of  hydrogen sulfide  in  1 m3     of  liquefied  
petroleum  gas.  Methyl mercaptan,  if  present,  produces  a  transitory  yellow stain  on  lead  
acetate  paper  which,  however,  fades completely   in  less  than  5 min.  Other   sulfur  com­
pounds present  in liquefied petroleum  gas do not in­ terfere with the test.

NOTE 1     Liquefied  petroleum  gases  and  the  products  of their combustion  should not be
unduly corrosive or reactive to materials with which they come into contact. It is there­ fore
important  that the presence of any hydrogen  sulfide, a highly  reactive  substance,  be  
detected.   Additionally,   the odour  of  hydrogen  sulfide is unacceptable  in some applica­
tions of liquefied petroleum  gases (e.g. lighter fuel).