Synthesis and characterization of Rhodamine based Pb²⁺ selective fluorescence sensor

We have synthesized and characterized a new Rhodamine-based Pb²⁺ selective fluorescent sensor. The fluorescent Pb²⁺ sensor Rh2 was synthesized by reaction of Rhodamine B with 2-bromoethylamine followed by sodium azide in high yield. We found that fluorescent sensor Rh2 exhibits a good selectivity toward Pb²⁺ over other metal ions in chloroform solution. In the absence of Pb²⁺, fluorescent sensor Rh2 is colorless and non-fluorescent, whereas pink color and strong fluorescence observed upon the addition of Pb²⁺. Since Rhodamine-based fluorescent sensor Rh2 exhibited simultaneous colormetric and fluorescence changes upon the addition of Pb²⁺, implying possible applications in a variety of area such as environment monitoring and diagnostic analysis.