Hi, Glen:

Is it enough for one overnight equilibration between water and CO2?  One
article says it takes five days. We use three days.

Regards.

Dachun Zhang
Isotope Lab
Zymax


"Glen E. Martin" wrote:

> Adam Porowski,
>
> We place  1 mL of sample water in a vacuum flask. Freeze the water, and
> evacuate the air.
> The water is melted, and the vacuum reaction flask (internal volume
> 10-20mL) is filled with CO2(g) to ambient (atmospheric pressure) minus 5 or
> 10 cms Hg (using a mercury manometer).The sealed sample is equilibrated at
> 25.3 degrees C overnight.
>
> The CO2(g) is extracted/purified the next day for analysis.
>
> G. Martin
>
>                     Adam Porowski
>                     <[log in to unmask]        To:     [log in to unmask]
>                     AN.PL>                 cc:
>                     Sent by: Stable        Subject:
>                     Isotope
>                     Geochemistry
>                     <ISOGEOCHEM@LIS
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>                     07/27/01 03:04
>                     AM
>                     Please respond
>                     to Stable
>                     Isotope
>                     Geochemistry
>
> Dear Isogeochem subscribers,
>
> I start to determine composition of stable isotope of oxygen (O18/O16) in
> groundwaters. I am going to use equilibration with CO2 method. Actually, my
> problem is how to bring up into the equilibration vessel proper, small
> amount of CO2 gas from the tank (I have rather bad - rude - pressure
> reducer in the tank). It means that I must do that on preparation line.
> Could you please advise me how do you do that action? Does the amount of
> CO2 for equilibration must be exactly the same each time (of course not
> bigger than the calculated max amount depending on volume of water taken to
> equilibration) or may be different?
>
> Thank you very much in advance.
> Best regards for all!
> #############################
> Adam Porowski
> Department of Hydrogeology
> Institute of Geological Sciences
> Polish Academy of Sciences
> ul. Twarda 51/55
> 00-818 Warsaw, POLAND
> [log in to unmask]
> tel: +48 22 697-87-56
> fax: +48 22 620-62-23