A new acridine derivative as a highly selective 'off-on' fluorescence chemosensor for Cd2+ in aqueous media

A new acridine fluoroionophore containing two diethanolamine ligands, 4,5-bis(N,N-di (2-hydroxyethyl)iminomethyl)acridine (BHIA), was designed and synthesized based on the fluorophorespacer-receptor format. And its fluorescent sensing behavior towards metal ions was investigated in buffered aqueous media. The presence of Cd2+ induces the formation of a 1:1 ligand/metal complex at neutral pH, which exhibits enhanced emission at 454 nm. The fluorescence intensity is linear with the Cd2+ concentration in the range of 1.0 x 10(-6) to 3.0 x 10(-5) M (R = 0.9967). Experimental results show a low interference response towards other metal ions. The selective switch-on fluorescence response of BHIA to Cd2+ makes it suitable for sensing of Cd2+ in aqueous solution. The detection limit is 1.3 x 10(-7) M. Moreover, the results indicated that BHIA was a reversible chemosensor for Cd2+, which makes it attractive for sensing applications. (C) 2011 Elsevier B.V. All rights reserved.