Ionic liquid-based chemodosimetric probe: the selective detection and removal of bisulfite from a pure aqueous system and potential uses in biosensing

Abstract

The simultaneous detection and elimination of harmful substances, such as bisulfite from a pure aqueous environment using simple probe molecules that can be reused is a crucial element in promoting sustainability. In this context, most homogeneous organic probes require organic solvents with water for sensing studies, and adequate majors are not taken towards remediation of these substances. Herein, we showcase a dual-functionality approach for selectively detecting and removing bisulfite using a straightforward ionic liquid-based chemodosimetric probe that can be recycled. We utilized a hydrophilic ionic liquid for the detection phase and a hydrophobic ionic liquid for the removal phase, and this removal agent can be regenerated under basic conditions. The chemodosimetric ionic liquid-based probe, featuring an aldehyde group, engages in a nucleophilic addition reaction with bisulfite, resulting in turn-on fluorescence through ICT breakdown, as corroborated by time-dependent density functional theory (TD-DFT) studies and fluorescence lifetime studies. Notably, the probe can differentiate bisulfite from sulfite, which share similar structures and properties, with remarkable sensitivity at the nanomolar level (91 nM). This probe was also employed to detect bisulfite in living organisms and quantify it in real samples. Thus, this study demonstrates the use of a simple, cost-effective, and recyclable ionic liquid-based probe for monitoring and mitigating bisulfite in pure aqueous systems.