Anomalous ions in the chemical ionization mass spectra of aromatic nitro and nitroso compounds

The appearance of [MH-30]⁺ ions in the chemical ionization mass spectra of aromatic nitro compounds may be due to their initial reduction to the corresponding amines within the ion source. Aromatic nitroso compounds may be similarly reduced to yield [MH-14]⁺ ions. The hydroxy derivatives of the nitroso compounds yield further anomalous ions at [MH-16]⁺ probably due to the reduction of the hydroxy groups.