The McLafferty rearrangement results in a prominent peak and often accounts for the base peak. Many other rearrangements are possible, even some that are not well understood and are considered ‘random’. McLafferty rearrangement for CH-C-C-C(=O)OH methyl acetate (C 3 H 6 O 2, M = 74) 43 M–31 74 M+ 59 M–15 S) E.I. The peak I can't identify is at 74. Rep. Prog. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, By continuing to browse this site, you agree to its use of cookies as described in our, I have read and accept the Wiley Online Library Terms and Conditions of Use. Long chain carboxylic acids are better identified by the fragments at CnH2n-1O2 (Figure 6.17). Investigation of c ions formed by N‐terminally charged peptides upon collision‐induced dissociation. If you do not receive an email within 10 minutes, your email address may not be registered, Aromatic acids have a more prominent molecular ion peak but undergo similar fractionation to short chain hydrocarbons. Aromatic acids can also lose water if an ortho group contains an abstractable hydrogen atom. In larger carboxylic acids these peaks are less prevalent. Journal of the American Society for Mass Spectrometry. While methyl ester versions of the metal cationized peptides primarily eliminate H2O following collisional activation and dissociation, the ethyl, propyl and butyl ester versions of the peptides exhibit a dissociation pathway consistent with γ‐hydrogen transfer to the C‐terminal carbonyl group, with associated elimination of an alkene, in a McLafferty‐type rearrangement. ions. One common type of rearrangement in MS is the McLafferty rearrangement which takes place in compounds that contain a carbonyl group. The full text of this article hosted at iucr.org is unavailable due to technical difficulties. Learn about our remote access options, Department of Chemistry, Wichita State University, Wichita, KS 67260‐0051, USA. International Journal of Mass Spectrometry. Which leads me to believe a loss of carbon monoxide. ion gave peaks corresponding to the ions at m/z 74, 75, 87 and 88, whereas the collision-induced dissociation spectrum showed low intensity ions at m/z 75 and 88 which come from double hydrogen rearrangement reactions of M+. The rearrangement leaves a metal cationized, free‐acid form of the peptide, as confirmed by comparing the multi‐stage CID of rearrangement products generated from peptide esters with the CID of corresponding metal cationized free‐acid peptides. In larger carboxylic acids these peaks are less prevalent. Rapid Communications in Mass Spectrometry. Copyright © 1995 Published by Elsevier B.V. International Journal of Mass Spectrometry and Ion Processes, https://doi.org/10.1016/0168-1176(95)04169-L.