Electron‐impact studies. LXXXII—Negative ion mass spectrometry of functional groups. Collision induced spectra of the carboxyl group

Fragmentations of the carboxyl group are not generally observed from molecular anions produced by the capture of slow electrons. Enhancement of the internal energy of the molecular anions by collision excitation allows the detection of the fragmentations of the substituent in the field free regions of the mass spectrometer. Fragmentations include the losses of CO2 or ·CO2H from molecular anions, and the elimination of CO2 from fragment ions.