Nanoparticle assisted cation adduction and fragmentation of small metabolites.

Abstract

Mass spectrometry (MS) promises small metabolite profiling as tool of the future and calls for comprehensive understanding of key procedures to enhance its capability. Herein, we studied cation adduction and fragmentation of small metabolites combining theoretical and experimental approaches, via nanoparticle assisted laser desorption/ionization (LDI)-MS and MS/MS. We calculated the energies of adduction conformers and atomic bond orders, to establish the rules of cation-metabolite affinity and multiple cation adductions in charge transfer. Further, we demonstrated the reaction paths of adducted ions and mapped the potential energy surfaces, to characterize the loss of given groups during fragmentation. Finally, we successfully controlled metabolite fragmentation by selected and multiple adductions, to enhance the atomic/fragment coverage as defined for metabolite identification toward profiling. Considering the success of MS in analysis of large biomolecules as honored by Nobel Prize in 2002, our work may have an impact and guide to advanced analysis of small metabolites.