Does deprotonated benzoic acid lose carbon monoxide in collision ‐induced dissociation?

AbstractDecarboxylation is known to be the major fragmentation pathway for the deprotonated carboxylic acids in collision-induced dissociation (CID). However, in the CID mass spectrum of deprotonated benzoic acid (m/z 121) recorded on a Q-orbitrap mass spectrometer, the dominant peak was found to bem/z 93 instead of the anticipatedm/z 77. Based on theoretical calculations,18O-isotope labeling and MS3 experiments, we demonstrated that the fragmentation of benzoate anion begins with decarboxylation, but the initial phenide anion (m/z 77) can react with trace O2 in the mass analyzer to produce phenolate anion (m/z 93) and other oxygen-containing ions. Thus oxygen adducts should be considered when annotating the MS/MS spectra of benzoic acids.

Source: Journal of Mass Spectrometry - December 26, 2023 Category: Chemistry Authors: Yingying Liu, Xue Wang, Danyang Zhang, Chen Wang, Haijiao Xie, Hongping Chen, Yunfeng Chai Tags: APPLICATION NOTE Source Type: research