The electron ionization-induced fragmentation patterns of three forensically relevant Schiff bases, originating from the condensation between 2-, 3- and 4-methoxyamphetamine and the corresponding ketones, were studied. The proposed fragmentation routes and ion structures are supported by high-resolution data and B/E linked-scan and mass-analyzed ion kinetic energy spectra. The rationalization of the ortho effect, which is responsible for the formation of the [M-OCH3] fragment in the case of the imine bearing ortho-substituted methoxy group, is given.
Copyright 2004 John Wiley & Sons, Ltd.