The hydroxyl-H from ethanol will exchange but the hydroxyl-O shouldn't. In organic reactions, ethanol conserves the oxygen since it reacts as ethanolate (C2H5O-), e.g. an ester made from ethanol and an organic acid (say, acetic acid) will contain the ethanol-O as ester bond (which is why one uses acetyl chloride or acetanhydride in acetylation reactions). Wolfram -----Original Message----- From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of peter kroopnick Sent: 23 October 2005 20:01 To: [log in to unmask] Subject: Re: Delta 18O of Formalin or Ethanol Dosn't the OH group exchange with water? If so, the O18 would be dependent upon the composition of the water. At 09:24 AM 10/21/2005 +0200, you wrote: Dear Andrea, my lab measured 3 sample of ethanol in the framework of an interlaboratory collaborative study among 11 labs in the world. The 18O values and sample description are as follows: 15.7 0 Vs. V-SMOW - alcohol 95% -1.4 0 Vs. V-SMOW- anhydrous synthetic alcohol 19.6 0 Vs. V-SMOW - anhydrous alcohol Hoping this could help you. Giorgio [log in to unmask] wrote: Hello, I was wondering if anyone has attempted to determine the delta 18O signature of 10% formalin or 85% ethanol. If so, what values did you obtain? Thank-you, Andrea ---------------------------------------- This mail sent through www.mywaterloo.ca -- *************************************************** Dr. Giorgio Capasso Istituto Nazionale di Geofisica e Vulcanologia Sezione di Palermo Via Ugo La Malfa, 153 90146 Palermo - ITALY tel. +39 091 6809436 +39 091 6809400 fax +39 091 6809449 e-mail [log in to unmask] *************************************************** Dr. Peter Kroopnick Home: [log in to unmask] Work: [log in to unmask]