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

Abstract 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, 1 H NMR, mass spectra and element analyses, it was noted to find that there was a simultaneously colorimetric response to Ag + and Fe 3 + accompanying with different color changes, i.e. , from brown to light purple for Ag + and further to purple-red for Fe 3 + , respectively. Their different action mechanisms, a 1:2 complex mode for EEPA -Ag + and 1:1 for EEPA -Fe 3 + , 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 Fe 3 + with the detection limits of 1.6 nmol·L − 1 and 69 nmol·L − 1 , respectively.