Dear Francesca,

yes - long-chain alkenone standards would be nice things to be able to
purchase ...
Up to date there is no commercial supplier available. What you can do in
order to ensure that your results are accurate:
Two years ago Toni Rosell-Mele send out some sediment samples and
synthezised 37:2+37:3 mixtures in a round robin experiment. Perhaps he
can spare some of his remaining batches ... He moved some weeks ago to
Durham: email there: [log in to unmask]
Some biological departments harvested their own "working standard" from
Haptophythes grown under known conditions and use them to ensure the
reproducibility of their measurements.
What most people do: Compare your results with those of "established"
alkenone labs, exchange some (sediment) samples and compare the results.
That will give a measure of reliability of the total procedure
(extraction-(fractionation)-measurement)  ...
Depending on the region where your "marine samples" are originating
from, you can choose between different protocols for alkenone
extraction-fractionation-saponification ... Up to now there is no
"standard protocol".

Have a nice day down in Trieste,

                                                    Christian.


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Christian Ostertag-Henning          tel: ++49-9131-852-2660 (office)
Institute of Geology                       ++49-9131-852-6243 (lab)
University of Erlangen-Nürnberg         fax: ++49-9131-852-9294
Schlossgarten 5
D - 91054 Erlangen                  email: [log in to unmask]

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