A Hg2+ selective fluorescent chemosensor based on rhodamine B thiohydrazide and its application in bioimaging

Abstract

A rhodamine B thiohydrazide-based fluorescent turn-on chemosensor (RN2) for Hg²⁺ was designed and described. RN2 exhibited very high sensitivity and selectivity towards Hg²⁺ over other metal ions. Due to the opening of the spiro ring in rhodamine B caused by Hg²⁺, the RN2 displayed selective ‘off–on’ type fluorescence enhancement and a distinct color change. The results of biological imaging studies demonstrated that this probe was cell permeable and could be used as a fluorescent probe for monitoring Hg²⁺ in living cells. The as-prepared chemosensor was also successfully applied to detect Hg²⁺ in environmental water samples.