Hydrogen scrambling in the long-lived protonated benzene ion generated from benzyl amine in the i.c.r. spectrometer

It is shown by reactions with various bases in an i.c.r. cell that an almost complete H-D randomization takes place in the gaseous and long-lived [C₆H₂D₅]⁺ ion, generated from C₆D₅CD₂NH₂ by electron impact, but not in its precursor ions. This follows from the ratio of [H]⁺ vs [D]⁺ transfer to bases, obtained from double resonance signals. The ratio appears to be reliable only if the protonated (deuterated) base is stable and does not undergo unimolecular decompositions.