Sulfur isotope compositions (33S/32S, 34S/32S and 36S/32S in the molecule SF6) of samples such as sulfide, sulfate or sulfur dissolved in glass are measured after extraction and chemical transformation into silver sulfide (Ag2S) and fluorination in nickel bombs, purification by cryogeny and gas chromatography, and isotope analysis by mass spectrometry (MAT 253).
The quantities generally used for analysis are > 6 μmol (1.5 mg of Ag2S) but we have increased our sensitivity to small samples down to 0.3 μmol (for isotope ratios 33S/32S, 34S/32S and 36S/32S) and hope to perform analysis on samples of only 10 nmol (for ratios 33S/32S, 34S/32S).
We are currently setting up the analysis of sulfur isotope composition in pyrites by fluorination coupled to laser ablation.
Finally, we started the measurement of S isotope composition in sulfate and sulfide (ratio 34S/32S) by elemental analyzer coupled to mass spectrometry (Delta Plus XP).
For further information, please contact Nelly Assayag and Pierre Cartigny.