Recent advancements in the detection of hazardous metal ions using rhodamine-based chemosensors

Rhodamine-based chemosensors have emerged as a prominent class of sensors for detecting harmful metal ions due to their excellent photophysical properties, such as high fluorescence quantum yields, large absorption coefficients, and strong fluorescence emission. This review comprehensively summarizes recent advances in the design, synthesis, and application of rhodamine-based chemosensors, specially fluorescent chemosensor, emphasised on the molecular structure, detection target ions, detection mechanism, detection limit, detection solution system, and performance of the rhodamine-based chemosensors. It highlights the mechanisms underlying their operation, including photoinduced electron transfer (PET), fluorescence resonance energy transfer (FRET), and ring-opening processes. This review has been classified by target harmful metal ions, such as Hg²⁺, Pb²⁺, Cd²⁺, Cr³⁺, Cu²⁺, Ni²⁺ and Zn²⁺. By improving the selectivity, sensitivity, and stability of these sensors, recent advancements address problems including environmental stability and interference from other ions. Furthermore, the range of detection in complicated environmental samples has increased with the introduction of novel functionalised rhodamine derivatives and hybrid sensor systems. The integration of rhodamine-based chemosensors into useful applications for tracking toxic metal ions in soil, water, and biological systems This critical review highlights the opportunities and obstacles for future research and innovation in the development of more sensitive, selective, and robust rhodamine-based chemosensors for the detection of hazardous metal ions.