Dear Listmembers,

We have the Isoprime-EA with ref gas box.
I have had varying degrees of difficulty with obtaining a constant flow of
SO2 from the ref gas injector. When I switch the injector back to nitrogen,
it operates perfectly again (maintains the same peak height), so the fault
is in the supply plumbing or gas cylinder or is there any other known
problem? For
instance I wonder if SO2 may condense in various parts of the system? The
line pressure from cylinder to ref gas box is just 2.5 bar, which seems to
be the pressure in the gas cylinder above the liquid.
Normally the peak height for reference gas injections does creep up or down
a bit, by several percent say, and I suspected that the regulator was not
stable in the
 low pressure range that I am using (~ 2 psi). This drift has become much
worse in
recent days, flow actually stopping during a run yesterday for no apparent
reason.
It's a cruddy grade of SO2, should I be drying/purifying this?
Any comments or hints on this subject would be most appreciated.

Robert Van Hale
Department of Chemistry
University of Otago
P.O. Box 56
Dunedin
New Zealand
pH/fax (+64)-3-479 7886
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