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

A new type of single-fluorophore-based fluorescent probes that displayed Ag + -selective TURN-ON and Hg 2+ -selective TURN-OFF type dual-channel antiphase-like fluorescence signaling features was developed, and their unique ability of enabling simultaneous determination of Ag + and Hg 2+ over other reference metal ions was confirmed. • New type of fluorescent probe for Ag + and Hg 2+ sensing with high selectivity and sensitivity. • First demonstration of single-fluorophore-based Ag + -selective TURN-ON and Hg 2+ -selective TURN-OFF type dual-channel fluorescence signaling system. • Single-fluorophore-based probes for simultaneous determination of Ag + and Hg 2+ without crosstalk. 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 CH 3 CN–MOPS mixed solvents with CH 3 CN/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 CH 3 CN–MOPS mixed solvents with the percentage of CH 3 CN 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.