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Stable Isotope Geochemistry

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From:
"Wassenaar,Len [NHRC]" <[log in to unmask]>
Reply To:
Stable Isotope Geochemistry <[log in to unmask]>
Date:
Thu, 26 Feb 2004 10:19:23 -0600
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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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