Novel triazine-based colorimetric and fluorescent sensor for highly selective detection of Al3+

This paper deals with a new fluorescent assay of Al3+ ions with (2,2′-(6-((4-nitrophenyl)amino)-1,3,5-triazine-2,4-diyl) bis(hydrazine-2-yl-1-ylidene)) bis(indolin-3-one) (NADO) containing triazine moiety developed over other commonly coexisting metal ions. The complexation activity of NADO with various metal ions in an ethanolic solution is specifically studied by means of fluorescent spectra. The NADO exhibits a significant fluorescence enhancement at 469 nm in presence of Al3+ due to the formation of a complex. Under an optimized condition the detection limit is found to be 0.09 μM. As the concentration of Al3+ is increased, the fluorescence intensity gradually increases due to the formation of the complex. The 1:1 binding stoichiometry between Al3+ and NADO is confirmed by the Job's plot and the HR-LCMS mass spectrum of the metal complex.