File talk:TFA spectrum 2000-4000-Esi-.jpg

How can this possibly be the mass spectrum of TFA in ESI negative mode?

To my knowledge (as an analytical chemist who sometimes uses TFA), TFA should give only two major peaks in ESI negative, them being 113 (deprotonated TFA molecular ion) and 69 (CF3-). However the peaks shown in the uploaded spectrum have masses that are far, far too high... looks more like a protein spectrum...


 * This is not the mass spectrum of TFA. This is clearly a polymer of some sort, not a protein, which you can quickly determine based on the fact that the m/z difference between adjacent peaks is constant (135.98 m/z).  If this were a mass spectrum of a protein the m/z difference between adjacent peaks would be increasing at higher m/z values due to the fact that proteins often have multiple charge states that show up in the same spectrum, and as the charge (z) decreases, the m/z of the protein of a given charge state increases.  Given that the m/z difference between the peaks in this spectrum is 135.98 m/z I would be inclined to say that this spectrum comes from dimeric polyisoprene (isoprene: monomer = 68Da; dimer = 136Da).  My best guess is something like C3H7- (CH2-C(CH3)=CH-CH2)2n -H.

Hello. It could be Cluster of TFA and Na. That's why there is less than 136 between each peaks. Is it High resolution? I'm not certain of this. Or maybe the lockspray is not active? — Preceding unsigned comment added by Johnfontan (talk • contribs) 14:31, 7 October 2012 (UTC)

M Meehan** —Preceding unsigned comment added by 128.54.22.68 (talk) 17:37, 31 July 2009 (UTC)