A quinoline-based ratiometric fluorescent probe for discriminative detection of Zn2+ and Cd2+ with different binding modes, and its Zn2+ complex for relay sensing of pyrophosphate and adenosine triphosphate

Abstract

A new and simple quinoline-based fluorescent probe for discriminative sensing of Zn2+ and Cd2+ has been synthesized by inserting an amide group into the 8-aminoquinoline fluorophore and a propargylamine chelating site. This easily-available chemosensor displayed selective and distinct ratiometric fluorescence responses to Zn2+ in almost totally water solution through its amide tautomer binding form, and to Cd2+ in CH3CN aqueous medium through its imidic acid tautomer binding form, respectively. Moreover, the in situ prepared probe 1–Zn2+ complex could act as a relay fluorescent sensor selectively toward pyrophosphate (PPi) and adenosine 5′-triphosphate (ATP) anions via further complexation. Thus, with good specificity, low detection limits and fast response time, a highly efficient fluorescence platform for simultaneous multi-analyte detection has been developed by using the uncomplicated single molecule. Finally, this multi-functional probe was applied successfully for analysis of all the target ions in the tap water sample and on test paper strips, and bioimaging of Zn2+ in mung bean sprouts with low phytotoxicity.