Dual application of a fluorene-based switch-on chemosensor for mercury and glutathione sensing in water: analyte-recognition-triggered self-assembly

Abstract

A versatile bifunctional fluorene-4 diethyl amino salicylaldehyde conjugate probe, L₁, was fabricated for visualization and quantitative analysis of Hg²⁺ and GSH separately in aqueous media. Probe L₁ exclusively showed rapid sensing toward Hg²⁺ (LOD = ∼17.35 ppb) and GSH (LOD = ∼25.83 ppb) with a significant “turn-on” fluorescence response, along with red-shifted emission maxima at 414 nm and 420 nm. Furthermore, the morphological transformation of the probe into self-assembled heterostructures occurred upon inclusion of Hg²⁺ or GSH owing to analyte-induced-aggregation emission. The sensing strategy was successfully implemented to recognize Hg²⁺ and GSH in contaminated natural water-body samples, simulated physiological media, and real biological samples, including human serum specimens. The visual and quantitative detection of Hg²⁺ and GSH using affordable test strips may offer great potential for rapid preliminary environmental monitoring.