Hi Anne:

 I've used a dichloromethanol and methanol for lipid extraction to prepare 
fish muscle and liver for analysis, and also collected the lipids. It is a 
method slightly modified from Ruiz et al 2007, and it seems very reliable 
given my replicate results.

Dichloromethanol and methanol are made up into two solutions at 1:2 and 
2:1 v/v. The freeze-dried, finely ground and screened tissues are first 
steeped in the 1:2 v/v solution for two hours, then centrifuged and the 
solution retained for extracted lipids. The sample is then steeped in the 
1:1 v/v solution for two hours, centrifuged, solution retained for 
extracted lipids, then the de-lipidised material washed exhaustively in 
deionized water.  I would suggest a preliminary rotary evaporation of the 
de-lipidised sample before freezedrying.

Ruiz, N., Dubois, N., Wielgosz-Collin, G., du Pont, T. R., Berge, J.-.P, 
Pouchus, Y. F., Barnathan., G. (2007). Lipid content and fatty acid 
composition of a marine-derived Trichoderma longibrachiatum strain cultured by agar surface and submerged
fermentations. Process Biochemistry 42, 676?680 

Dr. Nancy Beavan Athfield, Rafter Radiocarbon
National Isotope Center, GNS Science
PO Box 31 312, Gracefield, Lower Hutt

DD 64 4 570 4650
FAX 64 4 570 4657

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Sent by: Stable Isotope Geochemistry <[log in to unmask]>
05/11/2009 07:06
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        To:     [log in to unmask]
        Subject:        Re: select solvents for lipid removal

While looking at the scientific literature, there seems to be quite a
spread of solvents used to extract lipids from tissues ultimately
analyzing the tissue for 15N & 13C.  New to this, I am trying to veer
from the chloroform/methanol solution.  Are there any other solvents
that people are happy using generating  accurate isotopic results?  I
ultimately plan on capturing the lipid fraction and analyzing 15N & 13C
as well as the lipid extracted muscle tissue.

Thanks, Anne

Anne M. Cotter
U.S. Environmental Protection Agency
Mid-Continent Ecology Division
6201 Congdon Blvd
Duluth, MN 55804
fax 218-529-5003
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