A novel fluorescent chemosensor based on a rhodamine 6G derivative for the detection of Pb2+ ion

A new selective fluorescent chemosensor based on rhodamine 6G derivative ( R1 ) has been designed and synthesized, which displayed highly selective and sensitive detecting for lead ion in aqueous solution. Sensor R1 was selective toward Pb 2+ ion by a light yellow to pink change for the visual detection of Pb 2+ ion. The fluorescence recognition processes of Pb 2+ was based on a binding induced ring-opening from the spirolactam (nonfluorescent) to acyclic xanthenes (fluorescent). Sensor R1 was excited with a 1:1 binding ratio and the linear response in the range of 1.0   ×   10 −8 –1.0   ×   10 −5   mol   L −1 with the limit of detection of 2.7   ×   10 −9   mol   L −1 (3σ/slope).