MgClO4 decomposes at 250 C.

When it is wet, I am not what it would do, but generally water of
hydration decreases decomposition/melting temperatures.

Its an odd idea combining the two.

Marilyn Fogel

> Hi Toti,
>
> I'm not sure about a maximum temperature for the MgClO4 trap, but one
> reason for having the trap as a separate unit is so that you can change
> the MgClO4 reagent without having to cool the reduction furnace. We
> typically refresh the MgClO4 every hundred or so combustions, whereas
> the reducer seems to be good for ca. 500 combustions.
>
> While I whole-heartedly favor reducing the parts count and number of
> fittings that could potentially leak, I think that you may cause more
> problems than you solve with your plan.
>
> We have have very good success building a leak-tight (as confirmed by
> looking at the 40Ar signal) MgClO4 trap from Swagelock fittings, and
> using the Ultratorr fittings (3/8") and a piece of 9mm (or 3/8" if
> available) glass tube. I can provide a parts sketch/parts list off line
> if you're interested.
>
> Good Luck,
> Carl Johnson
> W.H.O.I.
>
>
>
> Toti Larson wrote:
>
>> Isotopists,
>>
>> Is there a maximum temperature that a Mg-perchlorate trap will work to
>> effectively remove water in an He-continuous flow? In an EA, for
>> example, can you pack the top of the copper reactor with
>> Mg-perchlorate (well above the hot zone/furnace, and separated from
>> the copper with quartz chips/quartz wool), rather than having a
>> separate Mg-perchlorate trap prior to the GC. At first glance the only
>> problem I can see is that the Mg-perchlorate will be hotter at that
>> position than it would be later down the line, and maybe the trap is
>> not effective at those temps. By touch, the outside temp of the quartz
>> tube is ~50°C in the region I am talking about (maybe its hotter in
>> the center of the tube?). Is there a flow concern I don't know about?
>> I know this probably sounds like a really bad idea, so don't ask why I
>> want to do such a thing. Briefly, I want to pass gas from my EA to a
>> GCMSD setup, and want to minimize the number of fittings (i.e. leaks)
>> that the Mg-perchlorate trap would present.
>>
>> Toti
>>
>
> --
>
>
>
> ***********************************************************
> ***********************************************************
> Mr. Carl G. Johnson
> Research Specialist
> Dept. of Marine Chemistry and Geochemistry
> 123 Fye Laboratory, MS#4
> Woods Hole Oceanographic Institution
> Woods Hole, MA 02543-1543
> USA
>
> Tel:  508-289-2304
> Fax:  508-457-2164
> [log in to unmask]
> http://www.whoi.edu/sites/MCG_OrganicMassSpectrometry
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>
>