Hi all,

I am forwarding a note from Maniko Solheid, at the University of Minnesota 
Stable Isotope Lab.

Cheers,
Ioan Lascu



Hi Ioan,

Here is my question to ISOGEOCHEM:

We are trying to establish methods to analyze DIC in water. We have a 
ThermoElectron Delta V Plus equipped with OI Analytical Aurora1030W (and 
autosampler 1088). Aurora1030W is connecting with DeltaV through Isomass 
interface and ConfloIII.

We analyzed some lake water samples for TIC and TOC with above equipment, 
and compared the results with ones obtained from an offline DIC extraction 
method. Isotopic composition of the manually extracted CO2 was measured 
using a Finnigan MAT252.

We noticed samples that contain larger amounts of TOC are offset from the 
values obtained from the manually extracted samples. I tested with our lab 
standard and the discrepancy still exists. I am suspecting a memory effect 
from organic matter.

Can anybody compare their analysis method for Aurora1030W with ours?

I did not mention the detail of my experiment to shorten the question. I 
can make it more detailed if needed.

Thank you,
Maniko

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