A sensor for selective detection of Al3+ based on quinoline Schiff-base in aqueous media

An efficient fluorescent Al3+ receptor, 4-N,N-diethylaminosalicylicaldehyde -(2′-methylquinoline-4-formyl) hydrazone (HL) has been synthesized and characterized by physico-chemical and spectroscopic tools. Upon addition of Al3+ to an aqueous solution of HL, it shows 125-fold enhancement of fluorescence intensity at 550 nm. Photoinduced electron transfer (PET) process, coupled with the intramolecular charge transfer (ICT) process, are proposed to explain the observed spectral response. The lowest detection limit for Al3+ is determined as 6 × 10−7 M in ethanol and water (4:1, v/v).