One further point - this works fine for air when only a few tens of
microlitres of gas are injected but attempts to inject larger volumes
of gas (eg N2 diluted in Helium) have failed. The addition of larger
volumes of gas seems to create a 'pressure wave' effect in the carrier
gas and the production of a false peak.  Perhaps this could be
overcome by changing from an SGE splitter valve to an open split at
the EA/Mass spec interface but I have not had the chance to
experiment. I would be interested in hearing comments on this.



Darren Sleep
Stable Isotope Facility
CEH Merlewood
Grange-Over-Sands
Cumbria LA11 6JU
UK
tel +44 (0) 15395 32264
fax +44 (0) 15395 34705