A Novel Pyridine and Julolidine Based Chemosensor for Al3+ Detection

In this work, a pyridine and julolidine based chemosensor (L) for Al3+ with a turn-on response in ethanol solution was designed and synthesized, whose emission intensity was enhanced by 85-fold in the presence of Al3+ by emitting bright green fluorescence at 480 nm. Meanwhile, the recognition process was hardly affected by other common cations. Based on the fluorescence titration data, the limit of detection (LOD) for Al3+ was estimated to be as low as 2.74x10(-8) M. Job's plot ascertained the coordinate stoichiometric of L to Al3+ as 1 : 1, with the association constant (Ka) of 7.24x10(3) M-1 depending on the Benesi-Hildebrand equation. The combined effects of photoinduced electron transfer (PET) and excited state intramolecular proton transfer (ESIPT) were proposed as the plausible coordination mechanism of L toward Al3+. Moreover, the application ability of L for determination of Al3+ was evaluated in water samples and with test strips.