Methyl transfer in field desorption mass spectrometry of ammonioalkanecarboxylate hydrochloride salts

Intramolecular methyl transfer has been observed previously in pyrolysis electron impact mass spectra of complex ammonioalkanecarboxylates. We present here field desorption mass spectra results of more simple N,N,N-trimethylammoniocarboxylate hydrochloride salts and their N,N,N-perdeuterotrimethylammonium analogs in which we observe methyl transfer. We demonstrate that mechanisms for this and other fragmentation and rearrangement processes are dependent on anode heating current. Addition of the protonating agent p-toluenesulfonic acid suppresses most ions except the protonated molecular ion.