Dear subscribers,

I have a student who is collecting water samples for dissovled inorganic carbon (C-13) and sulfide (S-34) analysis (both at 100's of ppm).  I usually add a few granules of solid HgCl to vials to inhibit microbial activity for  samples lacking sulfide,  but I'm worried about sequestering Hg as HgS, potentially compromising both C-13 and S-34 analyses.

Can anyone please offer advice or a protocol for such samples (different way to "poison" samples)?  I apologize in advance if this issue has been broached recently.

Chris Romanek
Savannah RIver Ecology Lab