A Novel High Selectivity Fluorimetric and Colorimetric Probe Based on Rhodamine B Hydrazide Derivatives for Detecting Hg2+ in Aqueous Media

Abstract

A colorimetric and fluorescent dual-channel chemosensor (G1) with a simple structure was designed and synthesized to identify Hg2+ in an aqueous solution with high selectivity and sensitivity. After adding Hg2+, the color of G1 in the dimethyl sulfoxide (DMSO)/H2O (2:8, v/v) solution changed from colorless to a distinct rose red, whereas the fluorescence changed from colorless to bright orange under ultraviolet (UV) light. The detection limit on the fluorescence response of G1 to Hg2+ was as low as 6.09 × 10-7 mol/L. The results of the Job’s plot suggested that the combined stoichiometry between G1 and Hg2+ was 1:1. By successively adding Hg2+ and ethylenediaminetetraacetic acid (EDTA), the fluorescence process can be reversed and almost no fluorescence loss. In addition, G1-based test strips were produced and were able to qualitatively detect Hg2+ in tap water.