Analysis of α-acyloxyhydroperoxy aldehydes with electrospray ionization–tandem mass spectrometry (ESI-MSn)
Article first published online: 9 JAN 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Journal of Mass Spectrometry
Volume 48, Issue 1, pages 79–88, January 2013
How to Cite
Witkowski, B. and Gierczak, T. (2013), Analysis of α-acyloxyhydroperoxy aldehydes with electrospray ionization–tandem mass spectrometry (ESI-MSn). J. Mass Spectrom., 48: 79–88. doi: 10.1002/jms.3130
- Issue published online: 26 DEC 2012
- Article first published online: 9 JAN 2013
- Manuscript Accepted: 18 OCT 2012
- Manuscript Revised: 17 OCT 2012
- Manuscript Received: 23 JUN 2012
- electrospray ionization;
- secondary organic aerosols;
A series of α-acyloxyhydroperoxy aldehydes was analyzed with direct infusion electrospray ionization tandem mass spectrometry (ESI/MSn) as well as liquid chromatography coupled with the mass spectrometry (LC/MS). Standards of α-acyloxyhydroperoxy aldehydes were prepared by liquid-phase ozonolysis of cyclohexene in the presence of carboxylic acids. Stabilized Criegee intermediate (SCI), a by-product of the ozone attack on the cyclohexene double bond, reacted with the selected carboxylic acids (SCI scavengers) leading to the formation of α-acyloxyhydroperoxy aldehydes. Ionization conditions were optimized. [M + H]+ ions were not formed in ESI; consequently, α-acyloxyhydroperoxy aldehydes were identified as their ammonia adducts for the first time. On the other hand, atmospheric-pressure chemical ionization has led to decomposition of the compounds of interest. Analysis of the mass spectra (MS2 and MS3) of the [M + NH4]+ ions allowed recognizing the fragmentation pathways, common for all of the compounds under study. In order to get detailed insights into the fragmentation mechanism, a number of isotopically labeled analogs were also studied. To confirm that the fragmentation mechanism allows predicting the mass spectrum of different α-acyloxyhydroperoxy aldehydes, ozonolysis of α-pinene, a very important secondary organic aerosol precursor, was carried out. Spectra of the two ammonium cationized α-acyloxyhydroperoxy aldehydes prepared with α-pinene, cis-pinonic acid as well as pinic acid were predicted very accurately. Possible applications of the method developed for the analysis of α-acyloxyhydroperoxy aldehydes in SOA samples, as well as other compounds containing hydroperoxide moiety are discussed. Copyright © 2013 John Wiley & Sons, Ltd.