A novel fluorometric chemosensor based on imidazo[4,5-b]phenazine-2-thione for ultrasensitive detection and separation of Hg2+ in aqueous solution

Abstract

We synthesize and develop 1,3-dihydro-2H-imidazo[4,5-b]phenazine-2-thione as a ratiometric chemosensor for recognition of Hg²⁺ in DMSO/H₂O (v/v = 9:1) binary solution. We rationally introduce the phenazine imidazole group as fluorophore and the thione moiety as recognition site to bind Hg²⁺. Interestingly, the chemosensor shows ultrasensitive response for Hg²⁺ and the lowest limit of detection is 0.167 nM. In addition, it can also separate Hg²⁺ from aqueous solution with excellent ingestion capacity, and the adsorption ratio is up to 96%. Furthermore, ion test strips based on the chemosensor are fabricated to conveniently and efficiently detect Hg²⁺.