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Stable Isotope Geochemistry

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Subject:
From:
David Katz <[log in to unmask]>
Reply To:
Stable Isotope Geochemistry <[log in to unmask]>
Date:
Thu, 26 Feb 2004 14:27:24 -0800
Content-Type:
text/plain
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Please remove me from the list serve,
Thanks,
Dave
----- Original Message -----
From: "Wassenaar,Len [NHRC]" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, February 26, 2004 8:19 AM
Subject: Re: [ISOGEOCHEM] Analysis of feathers


> Ramon,
>
> Cleaning of feathers is required for various reasons, but mainly if they
are
> dirty or bloodied (ie often with hunter supplied samples), and to get rid
of
> the surface oils which affects 13C and 2H, but not 15N.  While not a
> certified standardized method, the procedure we have used for over 10
years
> is:
>
> 1. 24 hr soak in 50/50 (vol/vol) chloroform/methanol, decant to waste
> 2. 2x sequential wash using 50/50 chloroform/methanol, decant to waste
> 3. Air dry in fume hood (24 hr). (caps off)
>
> A detergent clean for obviously dirty samples may precede the above steps
> (rarely).  I would not recommend the use of NaOH unless there is reason to
> believe there is soil or other organic matter adhering (ie for buried or
> archaeological samples).
>
> For the above prep procedure the most efficient way is to put and leave
your
> individual feathers in glass scintillation vials with plastic cap liners.
> These come in flats of 100 (box of 1000) and are very convenient.  Be sure
> to tape the sample label completely over with scotch tape so the solvent
> does not wash the label away.
>
> Never try to grind individual feathers (unless you need a large batch as a
> working reference). This not only pointless, but extremely difficult and
> frustrating unless you have a cryogenic grinder. Just cut the amount of
> feather vein material needed (300 ug to 1.5 mg) from the same location on
> each feather using small surgical scissors.
>
> See also:
>
> Wassenaar, L.I. and Hobson, K.A. 2002. Rapid online technique for
> determinations of non-exchangeable dD of keratins for animal migration
> studies. Isotopes in Environmental and Health Studies 39: No. 1-7.
>
> Len
>
> -----Original Message-----
> From: Ramón Redondo [mailto:[log in to unmask]]
> Sent: Thursday, February 26, 2004 6:22 AM
> To: [log in to unmask]
> Subject: [ISOGEOCHEM] Analysis of feathers
>
> Dear collegues,
> We are going to analyze d 13C and d 15N in feathers of birds. We have
being
> searching through the literature a standardized method to treat the
samples
> prior to the analysis (washing with NaOH, chloroform or detergents,
> grounding, etc) but we haven't found agreement.
> I would prefer do not pretreat the sample chemically. Why do you think is
> necessary to clean the feathers before the analysis?. Many thanks for the
> suggestions.
>
> Ramón Redondo
> Laboratorio de Isótopos Estables
> Universidad Autónoma de Madrid. Spain.
> Tel. 34 914974898
>

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