A highly effective curcumin analogue as naked eye colorimetric and fluorescent sensor for sensitive and selective detection of Hg2+ ions and its application on test strips and real sample analysis
A thiophene appended curcumin-based colorimetric and fluorescent receptor (TAA) for selective recognition of Hg2+ ions was synthesized and characterized using 1H NMR, 13C NMR and LC-MS spectroscopic techniques. TAA facilitates detection of Hg2+ by a naked-eye color change from yellow to colorless in visible light, and fluorescence turn-off in UV light (365 nm). The observed fluorescence quenching is due to the chelation-enhanced fluorescence quenching (CHEQ). TAA exhibited excellent selectivity and sensitivity toward Hg2+ ions, even in the presence of competing cations. The binding constant (Ka) for Hg2+ ions was found to be 3.4 105 M?1, indicating a strong binding affinity. The binding mechanism was elucidated using DFT calculations and supported by LC-MS and FT-IR studies. TAA forms a 1 : 1 complex with Hg2+ ions, as confirmed by Job's plot analysis. Additionally, the colorimetric limit of detection was found to be 0.67 ?M, while the fluorometric limit of detection was found to be 0.24 ?M, which demonstrates the high sensitivity of TAA towards Hg2+. Furthermore, TAA probe exhibited successful detection of Hg2+ ions in real water samples. Also, it can serve as an effective on-site detection tool for mercury ions by a simple test strip method that requires no additional instrumentation. 2025 The Royal Society of Chemistry.
RSC Advances;Volume;15;Issue;32;pp.25811-25822
All Open Access; Gold Open Access; Green Open Access
https://doi.org/10.1039/d5ra03656a https://www.scopus.com/pages/publications/105011525876?origin=resultslist
Ramesh D.K., Department of Chemistry, Christ University, Hosur Road, Karnataka, Bangalore, 560029, India, Centre for Renewable Energy and Environmental Sustainability, Christ University, Bangalore, 560029, India; Pujar P.P., Department of Chemistry, Christ University, Hosur Road, Karnataka, Bangalore, 560029, India, Centre for Renewable Energy and Environmental Sustainability, Christ University, Bangalore, 560029, India