Single-fluorophore-based fluorescent probes enable dual-channel detection of Ag⁺ and Hg²⁺ with high selectivity and sensitivity.

A new type of fluorescent probe capable of detecting Ag(+) and Hg(2+) in two independent channels was developed in the present work. Specifically, in CH3CN-MOPS mixed solvents with CH3CN/MOPS ratio (v/v) of 15/85, this type of probe fluoresced weakly, and the addition of Ag(+) remarkably induced fluorescence enhancement of the probe. In CH3CN-MOPS mixed solvents with the percentage of CH3CN increased up to 65%, the probe was highly fluorescent and addition of Hg(2+) dramatically induced the fluorescence quenching. Thus, using such single-fluorophore-based probe and tuning the polarity of the mixed solvent, Ag(+), and Hg(2+) can be detected in independent channels with high selectivity and sensitivity. As a result, the mutual interference usually encountered in most cases of Ag(+) and Hg(2+) sensing owing to the similar fluorescence response that these two ions induced, can be effectively circumvented by using the probes developed herein.