Dual sensitive and selective sensor for Pb2+ and Al3+ with distinctive fluorescence response

A Rhodamine B based dual-response sensor was developed for the independent sensitive and selective fluorescence sensing of Pb2+ and Al3+. Initially, TQ1 exhibited one major fluorescence emission peak centered at 461 nm in ethanol/HEPES solution (1/5, pH 7.4), where HEPES was 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid. After the addition of Pb2+, an obvious red shift of 55 nm in fluorescence emission can be clearly observed, accompanied by a fluorescence color conversion, from bluish violet to greenish yellow under 365 UV light. As for Al3+, the fluorescence emission of TQ1 experienced a much more remarkable red shift of 124 nm, and its fluorescence color also changed to red. Furthermore, the fluorescence sensing process of Pb2+ and Al3+ were completely independent and free from interference of each other via changing the buffer concentration. Detection limit of the probe TQ1 towards Pb2+ and Al3+ were 8.3590 x 10(-7) M (linear range 1.6-10.0 mu M) and 1.0568 x 10(-8) M (linear range 1.0-10.0 mu M) respectively. The complexation properties of TQ1 toward Pb2+ and Al3+ were studied in detail. (C) 2017 Published by Elsevier B.V.