Verification of Protonation Susceptibility of Functional Groups in Chemical Ionization Mass Spectrometry. A Cross Check

Abstract

In order to demonstrate the validity of the protonation susceptibility of pertinent functional groups, the chemical ionization mass spectra were measured for bifunctional aromatic compounds of the type p-XCH₂-C₆H₄-CH₂Y, where X=OH and NH₂, Y=OCH₃ and N(CH₃)₂. The relative protonation susceptibilities obtained from the observed spectral data are in good agreement with those available from other pairs of compounds reported previously. The order of the susceptibilities is not even qualitatively parallel to that of the proton affinities of these functional groups, and the result therefore indicates the protonation susceptibility being a significant and useful parameter in interpreting the chemical ionization mass spectra.