The formation of [M+H] + ions in EI mass spectrometry of 2(pyridil)ethanol isomers

The unusual formation of [M+H]+ ions in the EI mass spectra of 2(pyridyl) ethanol isomers has been studied with the aid of linked scans, low electron energy measurements and by relating the relative abundances of the M+· cluster with respect to the ion source pressure. The similar behaviour of the three examined isomers excludes the presence of “ortho” interactions. The easy formation of [M+H]+ ions may be explained by a capto-dative effect, deriving from the formation of particularly stable radical species.