DMA shows a similar distribution of PDMA confirming a comparable complexation ability of the two ligands. Since PDMA's chemical structure and complexation ability are analogous to that of DMA, we expect a similar chemical behaviour for the two ligands. The formation of Zn II -DMA complexes in solutions with ionic strength between 0.02 and 0.1 M starts at around pH 4 instead of pH 5 for PDMA. As observed for PDMA, the formation of Zn-DMA complexes shifts to higher pH range as consequence ionic strength increases.