A Turn-on Fluorescent Sensor For Cadmium Ion Detection In Aqueous Solutions

Fluorescent sensors have attracted an important interest due to their advantages such as high selectivity, rapid response, easy to use etc. In this study, a rhodamine based fluorescent sensor, RhDP, was synthesized, and used for selective detection of Cd 2+ ions. The sensor responds to Cd 2+ via the coordination induced fluorescence activation (CIFA) mechanism. RhDP gives a very fast and reversible fluorescence response to Cd 2+ in the presence of the metal ions tested. The complex stoichiometry between RhDP and Cd 2+ was found to be 1:1 and the binding constant was calculated as 2.70 × 10 7 M -1 in ACN/HEPES buffer (10 mM, pH: 7.05, v/v 1:1). The fluorescent detection limit of RhDP for Cd 2+ was found to be 0.218  µ M, which gave a marked sensitivity towards Cd 2+ .