MALDI TOF post-source decay investigation of alkali metal adducts of apolar polypentylresorcinol dendrimers

Polypentylresorcinol dendrimers of generation two and three with varying focal groups and terminal tetrahydropyranyl (THP) ethers could be efficiently ionized intact as their alkali metal ion adducts by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOP) mass spectrometry using α-cyano-4-hydroxycinnamic acid matrix. Post-source decay (PSD) MALDI TOF experiments were carried out to confirm the dendrimer structures. Li and Na ion adducts consistently produced far more intense fragmentation, unlike K and Cs ion adducts which did not produce any noteworthy fragmentation. Fragment structures and pathways were proposed on the basis of these findings. A major route of decay is the sequential loss of terminal THP ethers which proved particularly useful in structure confirmation. Li was shown to be the cation of choice to aid the analysis of THP containing polypentylresorcinol dendrimers.