title: Interactions of dissolved humic substances with oppositely charged fluorescent dyes for tracer techniques.
abstract: To investigate interactions between oppositely charged fluorescent dyes and dissolved humic substances, fluorescence quenching of fluorescein and rhodamine 6G with dissolved humic substances was performed. Binding coefficients were obtained by the Stern-Volmer equation. The fluorescence of rhodamine 6G was largely quenched by the addition of humic acid and a non-linear Stern-Volmer plot was obtained. This strong quenching may be caused by the electrostatic interaction between cationic rhodamine 6G and humic acid and strengthened by the hydrophobic repulsion. In contrast, the quenching and interactive effects of dissolved humic substances for fluorescein were relatively weak.
authors: Department of Integrated Science and Engineering for Sustainable Society, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan. Electronic address: hafuka.14p@g.chuo-u.ac.jp.
authors: Akira
authors: A
authors: Hafuka
authors: Division of Civil and Environmental Engineering, Graduate School of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan. Electronic address: dingqing1988@gmail.com.
authors: Qing
authors: Q
authors: Ding
authors: Department of Integrated Science and Engineering for Sustainable Society, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan. Electronic address: yamamura.10x@g.chuo-u.ac.jp.
authors: Hiroshi
authors: H
authors: Yamamura
authors: Division of Environmental Materials Science, Graduate School of Environmental Science, Hokkaido University, North-10, West-5, Sapporo 060-0810, Japan. Electronic address: yamada@ees.hokudai.ac.jp.
authors: Koji
authors: K
authors: Yamada
authors: Division of Environmental Engineering, Graduate School of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan. Electronic address: qsatoh@eng.hokudai.ac.jp.
authors: Hisashi
authors: H
authors: Satoh
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D019793:Fluorescein / Q000032:analysis*; D005456:Fluorescent Dyes / Q000032:analysis* / Q000378:metabolism; D006812:Humic Substances / Q000032:analysis*; D057927:Hydrophobic and Hydrophilic Interactions; D012235:Rhodamines / Q000032:analysis*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D006812:Humic Substances; D012235:Rhodamines; C026188:rhodamine 6G; D019793:Fluorescein
keywords: Fluorescein; Rhodamine 6G; Stern–Volmer plot; Tracer