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Kim
        I have used DRAGER tubes in line to remove H2S from carbonate 
CO2.  It is easy to install in line and it works well.  You will find 
these at Health and Safety retaillers. They are meant to "sniff" the 
presence of H2S in an environment.   It can be attached to to 
your line by Swadelock or Cajon ultra-torr union. 
   The reaction is  H2S+Pb(+2)---- PbS+2H(+).  The colour change 
gives a good indicator on when you need to replace it.
   For the second part of your question, analysing the S from the 
H2S.  You will find some information on in the Kiba technique for 
analysing total silphur in rocks.  The evolving H2S is precipitated 
in cadmium or zinc acetate.  We used to take cadmium acetate and went 
to zinc acetate.  It works just as well and in some cases, better.
     If you wish to precipitate the sulphide in a water sample, the 
methode used is often Cd acetate.   However we have found that in 
more than 80% of our sampling that the precipitate would give less 
than 30% yeild after combustion.  Whith zinc acetate we got 
consistently over 95% yeilds and regularly 100%.  I suspect that the 
Cd is somehow picking up other components of the water and 
contaminating  the sulphide sample.  The isotope results were not 
consistent as opposed to the zinc acetete.

Gilles 
sul
Gilles St-Jean, U. d'Ottawa / Geologie
140 Louis Pasteur, Ottawa, Ontario, Canada, K1N 6N5
Tel: 613 562-5800 ext: 6839(Bureau / Office)
     613 562-5800 ext: 6836(Lab)
Fax: 613 562-5192