Dear Jason,

Pure ethanol may leach out some hydrophobic components, but after decanting and thorough evaporation of the ethanol the bulk organic carbon isotopic value of the residual fossil organic matter will not be affected much. I would be more concerned if the alcohol was denatured and was added in excess. Denatured ethanol contains reactive substances like formaldehyde that can chemically react with the fossil organic matter and thus shift the isotopic composition. Taking a sip of the supernatant alcohol will probably not tell you very much. Maybe a wine or whiskey connoisseur can easily sniff out the difference between pure and denatured alcohol :-).

Best wishes,

Arndt Schimmelmann

On 1/26/2017 9:58 PM, Jason Curtis wrote:
[log in to unmask]" type="cite"> Hi All,

I have searched the Isogeochem archives for an answer but did not find one so I will ask again about preservation in alcohol.  A lab user has a bunch of amazingly well preserved Pleistocene leaves from Colombia that unfortunately were stored in alcohol before he got them.  He is interested in running bulk carbon isotopes on them.

I have read the Hobson et al., 1997 and Barrow et al., 2008 articles on various methods of preservation of animal tissue.  My understanding of the results is that 70% ethanol has little or no affect on the isotopes of animal tissue.  But I need input from the community on if alcohol preserved plant leaf samples are ruined for carbon isotopes.

I realize that alcohol will strip some specific molecules from the plant tissue but my hope is that bulk isotopes might still be good.  I am tempted to run them and report the results with the caveat that they were previously stored in alcohol.

Any input would be appreciated.


Jason Curtis, Ph.D.
Stable Isotope Mass Spec Lab manager
Senior Associate-In Geochemistry
Department of Geological Sciences
University of Florida
Gainesville, FL 32611

Arndt Schimmelmann, Ph.D. 
Senior Scientist 
Indiana University 
Department of Geological Sciences 
1001 East 10th Street 
Bloomington, IN 47405-1405
Ph   (812) 855-7645
FAX  (812) 855-7899 
e-mail:   [log in to unmask]