The fluorescence quenching behavior of rhodamine 6G (R6G) by graphene oxide (GO) under varying pH conditions was investigated. Utilizing steady-state fluorescence spectroscopy, single-photon counting, and ultrafast time-resolved absorption spectroscopy, we explored the quenching efficiency at pH values of 3, 7, and 11. Our findings reveal that GO effectively quenches R6G fluorescence across all tested pH levels, with the most significant quenching observed at pH 7. This quenching efficiency is attributed to optimal electrostatic interactions and efficient charge transfer between GO and R6G at neutral pH. At pH 3, the quenching efficiency is moderately reduced due to partial protonation of GO, which weakens electrostatic interactions but maintains hydrogen bonding. At pH 11, the quenching efficiency is lowest, likely due to increased electrostatic repulsion and reduced charge transfer resulting from deprotonation of GO. Ultrafast time-resolved absorption spectroscopy further confirmed the dynamic nature of the quenching process, showing distinct differences in relaxation kinetics across the pH spectrum. This study highlights the critical role of pH in modulating the quenching mechanisms of GO and R6G, providing valuable insights for the design of pH-sensitive fluorescence sensing systems.
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http://dx.doi.org/10.1002/bio.70055 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
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Birla Institute of Technology & Science Pilani - Hyderabad Campus, Chemistry department, Shameerpet, 500078, Hyderabad, INDIA.
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View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
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View Article and Find Full Text PDFSe Pu
January 2025
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
17-Estradiol (E2) is a natural steroidal estrogen essential for a variety of physiological functions in organisms. However, external E2, which is renowned for its potent biological effects, is also considered to be an endocrine-disrupting compound (EDC) capable of disturbing the normal operation of the endocrine system, even at nanogram-per-liter (ng/L) concentrations. Studies have revealed that medical and livestock wastewater can be contaminated with E2, which poses potential risks to human health.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Department of Chemistry, College of Arts and Sciences, Northeast Agricultural University, Harbin 150030, PR China. Electronic address:
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