Steady-state and Time-resolved fluorescence spectroscopy of aquatic humic substances (HS) isolated from Suwannee River and Nordic Lake produced by IHSS

miscellaneous

English

Four aquatic humic substances (HS) were characterized using advanced fluorescence techniques. Steady-state fluorescence (fluorescence excitation and emission, excitation-emission spectra – EEM) as well as time-resolved fluorescence spectroscopy were applied. The fluorescence decay of aquatic HS samples (Suwannee River Fulvic Acid, Nordic Lake Fulvic Acid, Suwannee River Humic Acid and Nordic Lake Humic Acid) was investigated using the time-correlated single photon counting technique (TCSPC). The fluorescence EEM spectra of aquatic HS were characterized by two unique fluorophores centered at an excitation/emission wavelength pair (EEWP) of 250–255/450–465 nm (peak A) and 305/440–455 nm (peak C). The fluorescence EEM spectra of NLHA and SRFA are located by prominent fluorescence maximum at the excitation/emission wavelength pair of ~ 250/330–340 nm (peak T) which is typical for protein-like material. The decay times in the range of τ1 = 0.22 ns ± 0.03 ns, τ2 = 1.2 ns ± 0.2 ns, τ3 = 3.9 ns ± 0.4 ns, and τ4 = 10.2 ns ± 0.8 ns with the largest contribution of τ3 were found for all aquatic HS investigated.

Aquatic humic substances; EEM spectrum; fluorophore; lifetime; relative amplitude

ENEV, V.; DOSKOČIL, L.; TÜRKEOVÁ, I.; KLUČÁKOVÁ, M.

11. 9. 2016

Nobuhide Fujitake (18th IHSS Secretary)

Laboratory of Soil Science, Department of Agricultural Science, Kobe University, 1-1 Rokko-Dai, Nada-Ku, Kobe 657-8501

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