Substituent effects in the field ionization mass spectra of acetophenones

Substituent effects in the electron-impact and field ionization mass spectra of acteophenones are compared. No Hammett correlation could be found for the fragments formed on the surface of the field anode. A straight line log z/z0 versus σ⁺ was observed, however, for the metastable decomposition of para-substituted acetophenones (and also some benzophenones). Meta-substituted compounds did not yield such straight lines.