Tandem Mass Spectrometric Studies on the [C5H8O2]+· Ions from Angeric Acid and Tigric Acid Esters

• Published in: Journal of the Mass Spectrometry Society of Japan 1999, Vol.47(5), pp.304-309
• Main Authors: SAKAI, Ikuo, TAJIMA, Tadakuni
• Format: Article
• Language: English
• Subjects: [C5H8O2]+· ion; Activation energy; Angeric acid (ester); Collision activated dissociation (CAD) spectrum; Computer aided design; Esters; Fragmentation; High energy collisional activation; Internal energy; Ionization; Low internal energy; McLafferty rearrangement; Metastable ion (MI) spectrum; Molecular ions; Spectra; Tandem mass spectrometry (MS/MS); Tight activated complex; Tigric acid (ester); α,β-Unsaturated carboxylic acid ester
• ISSN: 1340-8097; 1880-4225
• DOI: 10.5702/massspec.47.304

Collision activated dissociation (CAD) spectra and metastable ion (MI) spectra of the [C5H8O2]+· ions from various esters of angeric acid and tigric acid have been studied. The [C5H8O2]+· ions formed upon the McLafferty rearrangement from the precursor esters of these acids were identified as the same structures of the molecular ions directly produced by electron impact ionization of angeric acid and tigric acid respectively on the basis of CAD spectral evidence. The cis-trans isomerization of the acids can occur during ionization or subsequent fragmentation of the lower internal energy ions which proceed via unimolecular metastable decompositions. We have provided an example that the isomeric ions can be distinguished by the ion abundance enhancement by high energy collisional activation on the specific fragmentation reactions of the [C5H8O2]+· ions.