Protonated and Sodiated Cyclophosphamide Fragmentation Pathways Evaluation by Infrared Multiple Photon Dissociation Spectroscopy

Cyclophosphamide (CP or CTX) is awidely used antineoplastic agent,and the evaluation of its efficacy and its impacts on the environmentare dependent on tandem mass spectrometry (MS (n) ) techniques. Because there is no dedicatedexperimental study to characterize the actual molecular nature ofthe CP fragments upon collision-induced dissociation, this work evaluatedthe chemical structure of the fragments of protonated and sodiatedCP and CP protonation sites by infrared multiple photon dissociationspectroscopy supported by density functional theory calculations.This study allowed us to propose a new fragment structure and confirmthe nature of multiple fragments, including those relevant for transitionsused for CP quantitative and qualitative analyses. Our results alsoshow that there is no spectroscopic evidence that can rule out theexistence of aziridinium fragments, making it clear that further studieson the nature of iminium/aziridinium fragments in the gas phase arenecessary.