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

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 Al 3+ in DMSO/H 2 O solution (7:3, v/v, 10   mM HEPES, pH 7.4) with relative low interference of other common metal cations. As a colorimetric sensor, the absorbance peak centered at 315   nm and 400   nm enhanced after the addition of Al 3+ , while the absorbance peak centered at 275   nm and 344   nm 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 495   nm 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 Al 3+ . A stoichiometric complexation of 1:1 molar ratio between LBD and Al 3+ was confirmed and the detection limit of LBD was found to be 9   nM.