A rhodamine-based dual chemosensor for the naked-eye detection of Hg2+ and enhancement of the fluorescence emission for Fe3+

Abstract

A novel fluorescent chemosensor based on trimesoyl chloride–rhodamine (TR) was successfully synthesized. Rising chromogenic and fluorogenic spectral enhancements could be observed in trimesoyl chloride–rhodamine (TR) probes when Hg²⁺ and Fe³⁺ were added, respectively. TR has shown selectivity for Hg²⁺ and Fe³⁺ with high sensitivity due to metal ion complexation induced photophysical “turn-on” signaling responses. The detection limit towards Hg²⁺ was 2.46 × 10⁻⁸ M as determined by the 3σ method. At the same time, fluorogenic spectral enhancements were observed in TR, which exhibits a superior sensitive and selective recognition towards Fe³⁺ with 4.11 × 10⁻⁸ M of the detection limit. The test strips were used for colorimetric and simple detection towards Hg²⁺, which might finally enable the advancement of the Hg²⁺ sensor in the field of on-site detection.