Matrix assisted laser desorption/ionization mass spectrometry of aryl ester dendrimers

A series of aromatic aryl ester dendrimers have been analyzed by laser desorption/ionization (LDI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, Both alkali metal and transition metal salts were successfully used to form ions of the type [Dendrimer + Metal](+). Silver ion attachment was achieved with both LDI and MALDI, Attachment of lithium and sodium ions was readily achieved by MALDI but the heavier alkali ions and copper ions were more selective in their behavior and thus less useful for general analytical purposes. MALDI mass spectrometry is shown to be a useful tool for dendrimer characterization and this approach provides further evidence for the successful synthesis and purification of these compounds by convergent routes. However, impurity ions present in reagents can complicate polymer analysis and the use of high purity reagents is recommended.