We have a patented automated process for kerogen isolation that avoids
fluorite formation during isolation and filters the isolate after each step
so none of the fine material is lost decanting.  The process is computer
controlled and takes 2-3 days.  It can also remove pyrite.  All our testing
indicates that the isolates are superior to manual methods.  If it would
help you, we would be glad to work with you.

Louis Elrod


>Hello Antonio,
>for nitrogen and carbon isotopes it should not make any difference.
>However, if you evaporate water in a hood, make sure that the ambient air
>is free of ammonia vapors.  By the way, I found that the Wedeking et al.
>method to prepare kerogens is much more labor-intensive than the one
>published by Robl and Davis (Organic Geochemistry 1993, vol. 20, p.
>249-255).  The latter has also other advantages, namely that it avoids
>some chemical artefacts that occur with the use of concentrated
>hydrochloric acid (chlorination of kerogen).
>                                   Good luck,
>                                            Arndt Schimmelmann
>
>On Thu, 12 Feb 1998, [log in to unmask] wrote:
>
>> Hello,
>> I am dealing with some carbon and nitrogen isotopes from kerogen matter
>> separated from Jurassic black shales. I am using the procedures of organic
>> geochemical analysis from Wedeking, Hayes & Matzigkeit ()  and i would like
>> to know if an isotopic fractionation could happen evaporating the sample
>> instead of dry freezing it.
>> I would be grateful if anybody could give me some tips.
>> Thank you
>> Antonio
>>
>> PS: Ciao Zac!
>>
>
>


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Louis W. Elrod
Research Scientist
Geotechnology Research Institute
Houston Advanced Research Center
4800 Research Forest Drive
The Woodlands, TX  77381

Phone:     281-364-6061
FAX:       281-364-6052
E-mail:    [log in to unmask]    (work)
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WebSite:   http://gtri.harc.edu
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~