Fast atom bombardment mass spectra of dihydroxybenzenes: Formation of radical cation adduct between sample and matrix

Abstract

AbstractUnder fast atom bombardment, dihydroxybenzenes form predominantly the M+· and [M + Matrix]+· ions. The second field‐free region metastable decomposition of the [M + Matrix]+· ion involves the loss of a neutral molecule of the matrix. In the case of the hydroquinone–matrix adduct ion, elimination of both the matrix and hydroquinone are observed. Surprisingly, alkali metal cationization also leads to the formation of abundant radical cations in which the acidic hydrogens have been replaced with alkali metal. The degree of this exchange varies among the isomeric compounds. The facile formation of radical cations and their adducts appears to be due to various factors such as the ionization potentials, redox potentials and the proton affinities of the dihydroxybenzenes and the analyte‐matrix interactions.