Dear Masumi,

may I suggest that your student reads the following reference that deals 
with the effects of various preservatives on d13C and d15N:

Kaehler, S. & Pakhomov, E.A. 2001. Effects of storage and preservation on 
the d13C and d15N signatures of selected marine organisms. Marine Ecology 
Progress Series 219: 299-304.

I would suggest you manually remove the exoskeleton or shell of the crab and 
target only muscle tissue from the pincers. In a trophic study you do not 
want the inorganic carbon component from the shell/exoskeleton.

hope this helps,

Sean

Sean Porter
Marine Biology Research Centre
Zoology Department
University of Cape Town
Private Bag X3
Rondebosch 7701
South Africa
082 5148014
033 3434163
----- Original Message ----- 
From: "Masumi YAMAMURO" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, May 20, 2008 1:13 PM
Subject: [ISOGEOCHEM] d13C and d15N of preserved crab


> Dear colleague,
>
> I need your help.
> My student is studying cave crabs, some of which may be rare to the
> specific cave.
> His major theme is systematics, but he also likes to know what is the
> major food source for each crabs.
>
> Is it possible to use ethanol or formalin preserved specimen to
> analyze d13C and d15N?
>
> I remember the similar question was raised before, but I did not keep
> the answer mail at that time.
>
> I would appreciate any information how to analyze the trophic level of
> carb. Do you remove the shell of the crab?
>
> Sincerely,
> Masumi
> -------------------------------------------------------
> Dr. Masumi YAMAMURO
> Professor & Guest researcher of AIST
> Department of Natural Environmental Studies,
> Graduate School of Frontier Sciences,
> The University of Tokyo
> 5-1-5 Kashiwanoha, Kashiwa, 277-8563
> JAPAN
> TEL/FAX: 81-47136-4770
> E-mail:[log in to unmask]
> http://staff.aist.go.jp/m-yamamuro/en_Folder/top_english.html
> (Last updated April 21, 2007)