Dear Shao-Yong,

you can dissolve the pyrite/chalcopyrite fraction by using the Cr(II)
reduction method (see for instance Canfield et al., 1986). Anhydrite
is not touched by this procedure. you can dissolve it from separate
batches.

Good Luck
Michael

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Dr. Michael E. Boettcher
Biogeochemie
Max-Planck Institut fuer Marine Mikrobiologie
Celsiusstr.1
D-28359 Bremen
FRG
Tel: 0421-2028-632