The mass spectrometry of volatile derivatives—IV: Aryl trifluoroacetates

All the fluoro derivatives investigated exhibit strong molecular ions, which in many instances are also the base peaks. All the compounds with the exception of the p ‐acetyl derivative exhibit ions due to the loss of COCF 3 and (CO + COCF 3 ) from the molecular ion. Loss of CO from the molecular ion ranks as an important fragmentation except in cases where loss of a methyl group gives rise to ions which probably possess a tropylium structure. Alkyl ring substituted compounds exhibit intense hydrocarbon ions, which are also consistent with a tropylium structure.