Dear Paul,

about two years ago I had a similar "drift" problem with our dual
inlet Finnigan MAT251. You did'nt specify the type opf your mass-
spec, but in our case it helped tremendously to take the capillaries
(on both sides) out of the squeezers, widen the squeezed point
carefully with a pair of pliers (a little, just that bit!) and glow them
red hot with a gas flame. Whatever contaminant there was, it
disappeared while constantly pumping. The zero-enrichment test
came back to what it used to be.

If in fact your bellows are the problem, the spectromat people in
Bremen/Germany may have some good and affordable ideas how
to fix the problem. Contact Hansi Wust <[log in to unmask]>

regards to all,

Uwe Horstmann


Dr. Uwe E. Horstmann
Council for Geoscience
P/Bag X112
0001 Pretoria
South Africa

Tel.: +27 12 841 1361
Fax.: +27 12 841 1278
cell: 082 408 3212
e-mail: [log in to unmask]