A New Molecular Probe for Colorimetric and Fluorometric Detection and Removal of Hg2+ and its Application as Agarose Film-Based Sensor for On-Site Monitoring

• Published in: Journal of fluorescence Vol. 30; no. 6; pp. 1531 - 1542
• Main Authors: Bhatt, Shreya, Vyas, Gaurav, Paul, Parimal
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2020; Springer Nature B.V
• Subjects: Analytical Chemistry; Aqueous solutions; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biomedicine; Biophysics; Biotechnology; Chemical sensors; Chemoreceptors; Colorimetry; Fluorescence; Hydrogels; Mercury (metal); Metal ions; Monitoring; Original Article; Sodium sulfide; Solid phases; Colorimetry; Fluorometry; NBD-based sensor; Detection and removal of Hg; Agarose film; On-site monitoring
• ISSN: 1053-0509; 1573-4994
• DOI: 10.1007/s10895-020-02625-9

A new molecule incorporating two units of 7-nitro-benzoxadiazole (NBD), bridged by m-xylylenediamine, was synthesized and characterized on the basis of analytical and spectroscopic techniques. The metal ion sensing property of this molecule was studied spectroscopically with a large number of metal ions. This study revealed that it can perform as a dual-channel probe for colorimetric as well as fluorometric detection of Hg 2+ . In presence of Hg 2+ , a substantial change in UV-Vis spectrum with the appearance of a new band at 545 nm and a distinct colour change from yellow to red was observed. In the fluorescence spectrum, the intensity of the emission band was substantially quenched only upon addition of Hg 2+ . No significant interference from any other metal ion used in this study was noted, the limit of detection (LOD) for Hg 2+ was found to be 60 and 10 nM for colorimetric and fluorometric detection method, respectively. This new chemosensor was used for removal of Hg 2+ from aqueous solution with 92% efficiency. For on-site monitoring and field application, this molecule was immobilized into the agarose based hydrogel film, which was used successfully for detection of Hg 2+ in water. The study on reversible behaviour of this chemosensor revealed that it can be recycled in solution as well as in solid phase by treatment with Na 2 S.