A light-responsive, highly sensitive probe to perceive mercuric ions in both water and biological samples using fluorescence, colorimetric & electrochemical techniques

Given the increasing levels of Hg 2+ in the environment and ecosystem, a simple highly fluorescent, colorimetric, and electroactive probe based on benzothiazolinic salt was developed to monitor its presence in environmental and biological samples. An abrupt change in fluorescence signal in solid-state was also observed caused by Hg 2+ ions. Cyclic voltammetry was successfully used to investigate the redox response of the probe for Hg 2+ ions. Due to the superior colorimetric/fluorometric properties of the probe, a simple, cost-effective paper strip was developed aided by a smartphone to enable visible, quick, reliable, and practical detection of Hg 2+ in environmental analysis. For the probe, a LOD value of 55 nM was witnessed for Hg 2+ ions in water using the electrochemical method, while the colorimetric method aided by a smartphone yielded an 80 nM LOD value. The probe exhibited low cytotoxicity for Hg 2+ detection in HeLa cells enhancing its potential application in biological and environmental science.