A novel polydentate ligand chromophore for simultaneously colorimetric detection of trace Ag+ and Fe3.

A novel polydentate ligand chromophore, 3,6-di-(N-ethyl-N-ethoxyl phenylazo) acridine (EEPA), was identified and synthesized. After its structure was characterized by FTIR, 1H NMR, mass spectra and element analyses, it was noted to find that there was a simultaneously colorimetric response to Ag+ and Fe3+ accompanying with different color changes, i.e., from brown to light purple for Ag+ and further to purple-red for Fe3+, respectively. Their different action mechanisms, a 1:2 complex mode for EEPA-Ag+ and 1:1 for EEPA-Fe3+, were investigated and confirmed by means of Job's plot and theoretical calculation. EEPA would be a potential colorimetric chemo-dosimeter for simultaneous detection of Ag+ and Fe3+ with the detection limits of 1.6nmol·L-1 and 69nmol·L-1, respectively.