On/off rhodamine based fluorescent probe for detection of Au and Pd in aqueous solutions

A water-soluble turn on/off rhodamine 6G based fluorescent probe for selective detection of Au and Pd ions in aqueous acidic solutions has been developed. The newly designed probe reacts with [AuCl4]− and [PdCl4]2− to generate a product with different optical properties. The probe undergoes a remarkable change in its absorption and emission spectrum upon addition of Au and Pd complexes that is associated with a discoloration and quenching of probe fluorescence. The probe exhibits near linear signal response and allows determination of Au and Pd content in aqueous solutions from 0.1 μM.