The mass spectrometry of volatile derivatives—II: N-alkyl trifluoracetamides

Under electron-impact, N-alkyl trifluoracetamides exhibit peaks due to CF₃]⁺ and M ? CF₃]⁺. Ions corresponding to COCF₃]⁺ are absent. The base peak in many straight chain derivatives occurs at m/e 126 due to alkyl radical loss from the molecular ion; the mass of this ion rising to m/e 140 in the α-substituted N-sec-butyltrifluoracetamide and to m/e 154 in the tert-butyl derivative. High resolution measurements on a number of peaks indicate that they originate by loss of HF from other fragment ions.