Competing fragmentation processes of <i>O</i>-acetyl-substituted carboxylate anions subjected to collision-induced dissociation.

ABSTRACT: Carboxylic acids containing an O-acetyl substituent were studied using tandem mass spectrometry (MS/MS). Decarboxylation was observed for deprotonated O-acetylmandelic acid, whereas deprotonated acetoxyacetic acid and acetylsalicylic acid fragmented by two competing pathways. In the lower energy process, the product ion was formed by intramolecular proton abstraction and subsequent neutral loss of ketene (CH₂=C=O) from the O-acetyl group. At higher collision energies, nucleophilic displacement of the O-acetyl group by the carboxylate group of acetoxyacetate yielded acetate (CH₃CO₂^-) as the more abundant product ion. The relative energetics computed for the reaction pathways of acetoxyacetate were consistent with the pr

SUBMITTER: Grossert JS 

PROVIDER: S-EPMC12314208 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature