Reactions of Hydantoin and Succinimide Anticonvulsants with Dimethyl Ether Ions in a Quadrupole Ion Trap Mass Spectrometer

The analysis of hydantoin and succinimide anticonvulsants was carried out using techniques of chemical ionization and collision activated dissociation (CAD) in a quadrupole ion trap. Dimethyl ether was used as the chemical ionization reagent gas to generate [M + H] + and [M + 13] + products, with the objective of determining whether the protonation and methylene substitution reactions occurred at the same site and whether the products provided the same structural information. CAD, including MS 3 , SWIFT double resonance experiments and deuterium-labeling studies suggest that protonation occurs on a nitrogen atom or carbonyl oxygen while methylene substitution occurs predominantly on the phenyl substituents. Both [M + H] + and [M + 13] + ions dissociate by similar pathways in which typically the attached proton or methylene group remains a spectator.