A novel ratiometric fluorescent probe based on coumarin derivative for the recognition of Al(III) and its application on test strips

A novel ratiometric probe (L) which was composed of chromone and coumarin moieties has been designed and synthesized for sensing Al3+ in EtOH in view of the internal charge transfer (ICT) mechanism. The free probe L exhibited a strong fluorescence emission at 477 nm, and the fluorescence emission here almost disappeared after adding Al3+ (10 equiv.) while a new peak appeared at 524 nm. This may be due to the enhancement of intramolecular electron transfer efficiency from donor to acceptor. In addition, this probe L could be form a 1:1 complex with Al3+, which could be explained by the ESI-MS spectra, and L had a low detection limit for Al3+ with a binding constant of 1.32 x 10(4) M-1 More importantly, L could be applied to a solid probe for rapid detection of Al3+ with a significant color change. (C) 2019 Elsevier Ltd. All rights reserved.