Field desorption mass spectrometry of 1‐methylpyridinium salts

Quaternary pyridinium salts were investigated by field desorption, field ionization and electron impact mass spectrometry. Thermal decomposition of the salts under field desorption conditions was found to give very abundant volatile products, identified as the dihydro analogues and the ‘methides’ of the cations. The formation of the volatile compounds, especially those with molecular weights corresponding to those of the (cation −1), (cation +1) and (cation +13) was studied in detail by deuterium and 13 C labelling experiments.