Panorama view of the ISL

Isotope Science Lab

Protocol for sampling of dissolved H2S in water for δ34S analysis in the ISL

The following describes one method for precipitatation of dissolved sulfide (H2S aq) from waters for subsequent δ34S isotope analyses.  Note: the precipitate collected is cadmium sulfide which is a bright yellow color, and once collected, should be stored in dark glass bottle as it is light sensitive. 

Reagents:

  • cadmium acetate

Apparatus:

  • 120ml dark flint glass bottle
  • small spatula

Field procedure:

  • Try to collect samples that are free of sediment and are as clean as possible
  • Rinse sample bottle 3 times before final filling
  • Do not prefilter sample
  • minimize contact with air as one of the challenges of obtaining reduced inorganic S species for isotope analyses is to prevent their oxidation during sampling
  • Fill 120 mL amber glass bottle full.  Leave no headspace
  • Add a pinch of cadmium acetate (crystals). A pinch equals ~5mg or about the amount of a small spatula scoop
  • Label the bottle with the sample ID + “δ34S-H2S(aq)”
  • Keep sample refrigerated if possible
  • ship bottles (well packaged) to the ISL for filtration and subsequent δ34S analysis

Note: capturing dissolved sulfides is a non-trivial process.  Read section: 26.3.2 Sulfur in the hydrosphere in the Handbook of Stable Isotope Analytical Techniques, Volume I, 1st Edition for more details. 

Ship (within 2 days ideally) to:

Isotope Science Lab

University of Calgary

Geosciences, ES #513

2500 University Dr. N.W.

Calgary, Alberta, Canada,

T2N 1N4

Attn: Stephen Taylor  (403) 210-6003

steve.taylor@ucalgary.ca

References:

Carmody R., Plummer L. N., Busenberg E. & Coplen T. B. (1998) Methods for collection of dissolved
sulfate and sulfide and analysis of their sulfur isotopic composition. U. S. Geol. Surv., Reston,
Virginia. Open-File Report 97-234: 91p.

Pier de Groot: Handbook of Stable Isotope Analytical Techniques, Volume I, 1st Edition, Chapter 26