Facile one-pot synthesis of bipyridine-based dual-channel chemosensor for the highly selective and sensitive detection of aluminum ion

Abstract

A bipyridine-based colorimetric/fluorometric chemosensor (LBD) was designed and prepared via a facile one-step synthesis with high yield, and the obtained chemosensor exhibited a specific detection performance toward Al3+ in DMSO/H2O solution (7:3, v/v, 10mM HEPES, pH 7.4) with relative low interference of other common metal cations. As a colorimetric sensor, the absorbance peak centered at 315nm and 400nm enhanced after the addition of Al3+, while the absorbance peak centered at 275nm and 344nm gradually decreased. Distinctive colorimetric transition of LBD from colorless to light yellow was also clearly discerned. Simultaneously, a significant turn-on fluorescence response of LBD at 495nm and an apparent fluorescence emission variation from non-fluorescent to strong bright cyan was also observed by naked eye, which can be ascribed to the inhibited C=N isomerization and photo-induced electron transfer (PET) in LBD after the addition of Al3+. A stoichiometric complexation of 1:1 molar ratio between LBD and Al3+ was confirmed and the detection limit of LBD was found to be 9nM.