Fabrication of an acylhydrazone based fluorescence probe for Al3+

A simple acylhydrazone derivative 4-chloro-N'-(pyridin-2-ylmethylene) benzo- hydrazide (CPBH) has been designed to be a fluorescence probe for Al3+. CPBH displays a highly sensitive and selective fluorescence enhancement with Al3+ among various metal ions, due to a reduced intramolecular charge transfer and chelation enhanced fluorescence mechanism. The limit of dection for Al3+ is 0.2 mu M (5.4 ppb), and the linear range is from 2 to 15 mu M (50-400 ppb, c(CPBH) = 20 mu M) in the low concentration while another linear range is from 20 to 80 mu M (540-2200 ppb, c(CPBH) = 100 mu M). The CPBH and Al3+ form a 2:1 coordination complex according to the ESI-MS, Job plots and spectroscopy data. The binding equilibrium constant K is about 4.69 x 10(4) M-1 and 3.68 x 10(4) M-1 based on the data from absorption and emission spectra, respectively. To conclude, CPBH can be used as a sensitive and selective fluorescent probe for Al3+. (C) 2016 Elsevier B.V. All rights reserved.