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 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