Dear Weifu,
Our lab uses Sulfix, 8-20 mesh, from Wako. (We order it in Germany, Wako Chemicals). We freeze the CO2 into a glass tube, together with a few grains of sulfix. The tube is sealed and placed in an oven at 480 C. during several hours. It is a bit time-consuming, but the material works very well.
Good luck.

Hi, Everyone
       We are currently working on some carbonate samples containing a relatively high S content. Thus the CO2 we extracted through phosporic acid digestion ends up with a very annoying S contamination, which was confirmed by the mass scan of the sample. At this moment, the exact nature of the contaminant hasn't been identified, presumably H2S or SO2. We have already tried several purification methods, including cryogenic separation, reacting with silver wire, GC separation etc. So far, the results are not satisfactory.  I wonder whether anyone can give me some more hints on this problem. (The sample size we are dealing with is usually around 60 micromoles.)
    Any suggestions and comments from you will be highly appreciated.

Anita Aerts-Bijma
Centre for Isotope Research, University of Groningen.

Centrum voor IsotopenOnderzoek (CIO), Rijksuniversiteit Groningen
Nijenborgh 4, 9747 AG  Groningen, Netherlands
tel +31-50-3634716   fax +31-50-3634738