Dual-channel fluorescent sensor for rapid Cu2+ and Fe3+ detection: Enhanced sensitivity and selectivity with triazole-substituted acridinedione derivative

The <b>AR-2</b> sensor, derived from a triazole-substituted acridinedione, exhibits distinct responses to Cu²⁺ and Fe³⁺ ions. It shows fluorescence enhancement in the presence of Cu²⁺ ions and a reduction in fluorescence with Fe³⁺ ions. This sensor is distinguished by its high sensitivity, selectivity, rapid response time, reversibility, and broad operating pH range, with shallow detection limits for both ions. Structural and photophysical analyses of <b>AR-2</b> were conducted using density functional theory (DFT) and various spectroscopic techniques. The binding modes and recognition mechanisms for Cu²⁺ and Fe³⁺ ions were elucidated through multiple experimental approaches. Additionally, <b>AR-2</b> demonstrated efficacy in the rapid, visual detection of these ions via paper test strips and swab tests. It successfully identified Cu²⁺ and Fe³⁺ ions in real water and food samples, achieving notable recovery rates. The <b>AR-2</b> sensor also excelled in fluorescence imaging, effectively visualizing iron and copper pools in seed sprouts.