Stable Isotope Geochemistry


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[log in to unmask] (Neil S. Summer)
Thu, 18 Jul 1996 11:30:22 -0400 (EDT)
text/plain (42 lines)

Hi Arnold,

Does your spillage occur on
 A) pump down or  B) on carousel advance.

If A  then pump down through a  longer capillary tube and only open  the
manual valve when  pirani 3 reads  approx 1e-4 (i.e. after about 5 minutes)

If B then check for a  burr or nub on the base of the metal boats (buckets)
and file down if present to get a smooth flat base. If the boats teeter on
such nubs they will fling your sample around as the carousel advances.

We regularly run foram and other shell and diagenetic carbonate samples
down to 50mg utilizing a method of alleviating spillage involving150 mcron
copper mesh and a eighth inch paper punch.
We punch out little circles of copper as mini-screens, and press them into
the boats with tweezers after loading sample. The meshdoes not impede
reaction and remain in the boats to be levered out after the run with a
hypodermic needle. We buy our punches at a stationary store for $2. If you
can't get them in Europe, I'll be happy to send you some. I'm sure the
copper cloth is available there, if not I'll give you the address of our
supplier in Newark NJ.

Alles van de beste,

Neil S. Summer
Stable Isotope Laboratory
Department of Geology
1112 Turlington Hall,
PO Box 117340
Gainesville, FL 32611-7340

email: [log in to unmask]
Phone: (352) 392-2296/31
FAX:       (352) 392-9294