Figure 4: Identification of metal–DMA and metal–NA complexes under physiological pH conditions.

The metal complex mixtures were prepared in pH 5.5 (a,c) and pH 7.5 (b,d) and identified with the released free metals (lower panel) in positive ESI mode with Obritrap-MS. The spectra of the released free metals were obtained in ESI-MS/MS with fragmentation energies HCD-90%. Asterisk denotes the ferric ion.