Characterization of ionophore–metal complexes by infrared multiphoton photodissociation and collision activated dissociation in a quadrupole ion trap mass spectrometer

The formation and fragmentation of a series of metal complexes containing polyether ionophores were studied using electrospray ionization (ESI) methods. Dissociation pathways were analyzed using both collision activated dissociation (CAD) and infrared multiphoton photodissociation (IRMPD) techniques. A number of structurally diagnostic fragment ions were observed, and in many cases the same types of pathways were observed for the alkali, transition, and alkaline earth metal complexes. The dominant fragmentation pathways included dehydration and cleavage across carbon–carbon bonds to produce either type-F or type-A fragments. Energy-resolved CAD and IRMPD experiments, along with double resonance SWIFT, were performed to evaluate the genealogy of fragmentation pathways.