Sulfur Isotope Extraction
Extraction lines for preparation of solid and liquid samples fur multiple sulphur isotope analysis. The purpose of the extraction lines is to precipitate sulfur from almost any type of samples as Ag2S, which is the form needed for the analysis of multiple sulfur isotopes (32S, 33S, 34S, 36S). The sample powders are put in the reaction bottles, and isolated from air by connecting the raction flask to a N2 circulation system. The reagents can be added later using a syringe and a septum port,
- Sulfates are reduced to H2S using so-called Thode Solution (HI + H3PO2 + HCl). The evolved H2S is then precipitated as ZnS, followed by Ag2S upon addition of AgNO3.
- ZnS can be purified using HCl and re-trapping the evolved H2S as ZnS, and reprecipitated as Ag2S.
- Sulfur in rocks can be extracted using Kiba reagent (H3PO4 + HCl + Sn-Chloride).
- Sulfur can be extracted from pyrite and other iron sulfides by boiling under N2 with reduced chromium solution.
The Ag2S produced are then analysed in Shuhei Ono's lab at MIT.
These lines are used mostly for the project on sulfur speciation and isotopes in geothermal waters