Fragmentation processes of methylbutyl trifluoroacetates studied by tandem quadrupole mass spectrometry and isotope labeling

✍ Scribed by Chang S. Hsu; Dan Fǎrcaşiu

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 931 KB
• Volume: 24
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210240906

✦ Synopsis

The fragmentation patterns of 3-methyl-2-butyl trifluoroacetate and %methyl3-butyl trifluoroacetate were investigated by GC/MS/MS, with electron impact and collision-induced dissociation, on regular and isotope-labeled (deuterium and '*O) esters. The atoms found in various fragments could be traced back to specific positions in the parent molecules. In this way, molecular rearrangements potentially occurring during the formation of esters by trifluoroacetolysis of 3-methyl-Zbutyl p-toluenesulfonate or trifluoroacetic acid addition to various 2methylbutems could be shown. Rearrangements also occurred during the fragmentation, particularly during the expulsion of the small fragments CO, C,H, and F,CO. For the decompositions of oxygencontaining ions these rearrangements were highly specific. By contrast, alkyl cations lead to fragments that are fully scrambled (statistical label distribution). Alkene radical cations ([C,,H,J'*) fragment to daughter ions that are extensively, but less than statistically scrambled. Hydrogen scrambling may also occur in fluoroalkyl cation fragments.