The reactions are done at 90oC.

-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]]On
Behalf Of Haraldur R. Karlsson
Sent: Wednesday, June 13, 2001 10:48 PM
To: [log in to unmask]
Subject: [ISOGEOCHEM] manometer calibration


>Dear Andy,
>We have replaced our mercury manometers with electronic manometers (Tylan
>General, San Diego, CA). We calibrate them for CO2 via CO2 generated from
>weighed calcite samples that are reacted in H3PO4. Precision and stability
>is excellent.
>
>Lowell
>
Andy and others,

I would avoid using carbonates for the calibration e.g. calcite since
you must assume 100% yield.   Calcite does not yield 100% at 25C. The
method I described is simply better.

Best wishes,

Hal Karlsson
--
Dr. Haraldur R. Karlsson
Associate Professor
Department of Geosciences
and Department of Chemistry and Biochemistry (joint)
Texas Tech University
Lubbock, TX 79409


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