Dear Osborn,

Something I've found that can sometimes produce SO2 tailing is if a
void space opens up in the combustion tube packing.  The leak check
procedure on our elemental analyser (we have a Eurovector EA here)
sometimes produces this, so after installing a new reactor, I run a
couple of EA leak checks, then take out the combustion tube to
inspect it.  If a void has opened up, I try to re-pack the column to
close up the void.  I've also found that it helps to have the EA very
"leak tight".  Once the Cu in the reactor is exhausted, the SO2 GC
peak shapes will become awful.  As Steve Silva mentioned, I've also
found that an ash build-up can cause SO2 tailing.

We use a significantly different flow rate and GC temperature, but
this may be due to differences between EA and mass spec systems.  For
what it's worth, we use a flow rate of 100-120 ml/min, and a GC
temperature of 85 C (we use an 0.8m teflon column, which I think is
packed with Porapak).

Hope this helps.

Cheers,
Simon




>Dear All,
>
>I am using Europa GC/C-IRMS system.I reconditioned the GC column at
>150 degrees
>centigrade overnight but still I am having 32S and 34S tailing peak which take
>an hour to come back to the baseline.Conditions are as following: Flow rate
>60ml/min, GC column 35 degrees centigrade, combustion tube 1020 degrees
>centigrade, GC column and combustion tubes
>  are from Europa.
>
>Does anyone have an explanation for why this is happening an how can we
>overcome
>this ?
>
>Regards
>
>Osborn

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Simon Poulson
Dept. of Geological Sciences MS-172
1664 N. Virginia St.
University of Nevada - Reno
Reno, NV 89557-0138. USA
(775) 784-1104
Fax: (775) 784-1833
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