Electrospray ionization mass spectra of monoimidazole/polyamine conjugates

Imidazole/polyamine amides are biologically important molecules due to their specific DNA binding activity, and much attention has been attracted to the synthesis of their derivatives or analogues. In the present studies, the fragmentation of a series of synthetic monoimidazole/polyamine amides was investigated using electrospray ionization mass spectrometry (ESI-MS) combined with tandem mass spectrometry (ESI-MS/MS). All of the monoimidazole/polyamine amides produced the fragment ion m/z 183 except for the monoimidazole/ethyldiamine amide. The diamine amides produced this ion after the elimination of an alkene, the triamine amides produced it via their corresponding diamine amide fragments, and the tetraamine amide via its triamine and then diamine amide fragments. The characterization of the mass spectra for the different polyamine amides allowed identification of a specific product from the N-acylation of spermidine, and should assist further study of the polyamine amides in DNA binding action.