An ionic liquid mediated green emitting nanoprobe for selective detection of Hg²⁺ ions

Mercury and its compounds pose serious health and environmental risks due to their high toxicity, persistence, and bioaccumulation, particularly in the form of Hg²⁺ ions. This study reports the synthesis of a yellowish-orange emitting ionic liquid (SLIL) via a simple ion-exchange method. The SLIL shows strong photoluminescence under 365 nm UV light, which changes notably when dispersed in water as a nanosuspension (nSLIL) in the presence of Hg²⁺ ions. The probe demonstrates excellent selectivity and high sensitivity, with nanomolar detection (LOD = 5.9 nM) and quantification (LOQ = 19.9 nM) limits, making it suitable for biological applications. Additionally, a portable paper-strip sensor was developed for practical on-site mercury detection. This work highlights a promising ionic liquid-based nanomaterial for efficient environmental monitoring.