Selective fluorescent detection of Zn 2+ by a rhodanine‐based chemosensor

A rhodanine‐based fluorescent chemosensor DHM , 3‐[(E)‐{[4‐(diethylamino)‐2‐ hydroxyphenyl]methylidene}amino]‐2‐sulfanylidene‐1,3‐thiazolidin‐4‐one, has been designed and synthesized. Sensor DHM showed unique optical properties with large fluorescence change on detecting Zn 2+ . Most cations did not disturb the binding of DHM with Zn 2+ , while Co 2+ and Cu 2+ displayed fluorescence quenching and Fe 2+ , Fe 3+ , and Ni 2+ did some interference. With outcomes of Job plot and electrospray ionization (ESI)‐mass data, the binding ratio of DHM to Zn 2+ was determined as a 1:1. Moreover, DHM could detect Zn 2+ with a low detection limit (1.33 μM). DHM could efficiently analyze Zn 2+ in a real environment with positive recovery and relative standard deviation (RSD) and be recyclable reliably with ethylenediaminetetraacetic acid (EDTA). DHM ‐doped test kits can be readily used for recognizing Zn 2+ . The binding feature of DHM to Zn 2+ was illustrated by ESI‐mass, nuclear magnetic resonance (NMR) titration, and calculations.