PBA/Rh6G dual-channel ratiometric fluorescence sensing platform for highly sensitive Ag+ detection

A PBA/Rh6G ratiometric sensing platform was constructed by simple fluorophore mixing. • The system enabled sensitive Ag  +  detection with a LOD of 6.8 × 10 −14  mol L −1 . • Ratiometric readout improved repeatability and enabled reliable analysis of real water samples. The sensitive and accurate detection of silver ions (Ag + ) is of considerable significance for environmental monitoring and health risk assessment. To address the susceptibility of single-channel fluorescence detection to variations in probe concentration, excitation intensity, and sample matrix effects, a dual-channel ratiometric fluorescence sensing system for Ag + detection was constructed by directly mixing 1-pyrenebutyric acid (PBA) and rhodamine 6G (Rh6G). In this system, PBA served as the Ag + -responsive unit and exhibited a characteristic emission at approximately 400 nm under excitation at 328 nm, with its fluorescence intensity decreasing as the total Ag + concentration increased. Rh6G provided a relatively stable reference signal at approximately 578 nm, and the fluorescence intensity ratio I 400 /I 578 was used as the ratiometric response parameter. Suitable conditions for dual-channel detection were established by systematically optimizing the concentrations of PBA and Rh6G, the DMSO volume fraction, pH, and reaction time. The results showed a good linear relationship between the ratiometric fluorescence signal and the logarithm of the total Ag + concentration (R 2  = 0.992), with a detection limit as low as 6.8 × 10 −14  mol L −1 . Preliminary analysis of spiked campus lake water samples yielded recoveries ranging from 95% to 105%. Without requiring complex nanomaterial synthesis or multistep surface functionalization, this method provides a simple strategy for constructing ratiometric fluorescence sensing systems for Ag + detection. Download: Download high-res image (310KB) Download: Download full-size image