What do you use to stop bacterial activity?
At 04:27 AM 1/16/2008, you wrote:
to the water equilibration
Linda Davis Anderson, Ph.D.
just a reminder, the isotope equilibration between H20 and H2 happens in
the vapor phase , so if there is no H2S in the vapor (depending on the pH
of the liquid ) then there is no poisoning of the catalyst surface. But
if you do have H2S in the vapor phase the catalyst will be inactive with
time. And a second reminder: the equilibration occurs on the catalyst
surface the catalyst has to be temperature controlled . some people place
the catalyst well above the liquid phase at the top of a bottle where the
temperature might be different by a few tenth of a centigrade compared to
the temperaturecontrolled liquid and therefore they get different
fractionation results. and a third thing: do not stop bacterial activity
with HgCl2 this ruins the catalyst
MS Analysentechnik (producer of the catalyst sticks)
Von: Jonathan Wynn <[log in to unmask]>
An: [log in to unmask]
Verschickt: Di., 15. Jan. 2008, 19:15
Thema: [ISOGEOCHEM] poisoning of D/H platinum rods/Hokko Beads by
dissolved sulfide, and copper pre-treatment
I've read in the ISOGEOCHEM archives that the Platinum catalyst used in
D/H analyses of H2O by equilibration can be "poisoned" by
dissolved sulfides. Does anyone have experience to estimate a sulfide
concentration above which this effect should be considered significant?
I've also read about pre-treatment with copper to avoid this problem.
Does anyone have a reference or advice for a standard pre-treatment?
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