Following the induction of hemin aggregation in a mixture of solvents comprising DMSO, ACN, H2O, FA (1%) (with ratios 0.04/1/1/0.04), four main species were observed. These were assigned to hemin obtained confirms the π-π stacking mechanism, while the other species (m/z 1249.1) corresponds to the addition of H2O to this dimer (fig. ). Here, the dissociation of [2M-H] + was studied by following the decay within the quadrupole chamber resulting mainly in the loss of a water molecule, while the formation of monomer [M + ] was observed with only small intensities. These results confirm the strong interactions in the formed dimer. Furthermore, the dissociation of hemin trimer resulted in the formation of both dimer and monomer ions (Supplementary fig. ). In addition, it should be noted that no aggregation of H-Styr, H-Tyra and H-Tyros was observed under the current experimental conditions.