Multi-channel detection of Au(III) ions by a novel rhodamine based probe

Ionic gold species display remarkable features in chemical and biological activities. However, high amount of gold ions, especially Au³⁺ ions (200 µM), seriously threaten living organisms and vital human organs. Therefore, accurate detection of Au³⁺ ions is highly desirable. In this work, a novel rhodamine based optical and electrochemical active probe, integrated with triphenylamine and thiophene moiety, exhibited highly selective detection of Au(III) ions compared to the other metal species, such as Ag⁺, K⁺, Li⁺, Na⁺, Hg²⁺, Ba²⁺, Ca²⁺, Cd²⁺, Cu²⁺, Co²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Pb²⁺, Zn²⁺ Pd²⁺, Al³⁺, Ce^3+, Cr³⁺, Fe³⁺ and Cr⁶⁺. Exploiting hydrolysis and ring-opening reaction, the probe offers privileged properties such as naked-eye detection (colorimetric), both “turn-on” and “turn-off” fluorescence responses, voltammetric read-out with an anodic shift, low detection limit (340 and 315 nM for “turn-on” and “turn-off”, respectively), rapid response, and applicability in determining Au(III) in complex water samples.