FLUORESCENCE DECAY OF HUMIC SUBSTANCES. A COMPARATIVE STUDY

1998 ◽  
pp. 113-122 ◽  
Author(s):  
Fritz H. Frimmel ◽  
Michael U. Kumke
Keyword(s):  
Comparative Study ◽  
Humic Substances ◽  
Fluorescence Decay

On-the-Fly Fluorescence Lifetime Detection of Humic Substances in Capillary Electrophoresis

2003 ◽  
Vol 57 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Joseph D. Hewitt ◽  
Linda B. McGown
Keyword(s):  
Humic Substances ◽  
Fluorescence Lifetime ◽  
Spectral Characteristics ◽  
Emission Spectra ◽  
Fulvic Acids ◽  
Fluorescence Decay ◽  
Fluorescence Excitation ◽  
Lifetime Analysis ◽  
Decay Profile ◽  
Fluorescence Lifetime Detection

On-the-fly fluorescence lifetime detection was investigated as a tool for studying humic substances in capillary zone electrophoresis (CZE). Humic substances are complex, heterogeneous mixtures of natural products that tend to migrate in a single, broad CZE peak. The intrinsic fluorescence lifetime of five humic substances from the International Humic Substances Society (IHSS) was monitored using excitation at 488 or 364 nm to produce intensity-lifetime electropherograms for each of the substances. Each frequency-domain lifetime measurement, collected at sub-second intervals during the CZE run, contains the equivalent of a complete decay profile. Lifetime analysis of each decay profile was used to construct a lifetime-resolved electropherogram for each lifetime component, from which the variation in relative intensity contributions of each lifetime across the broad CZE peak could be determined. Absorption spectra, fluorescence excitation–emission spectra, and lifetime profiles of batch solutions of the samples were determined as well. It was found that, whereas absorption and fluorescence spectral characteristics tended to discriminate between humic acids and fulvic acids, the batch solution lifetime profiles discriminated instead between samples from different sources, regardless of fraction. On-the-fly lifetime detection provided a more detailed view of the fluorescence decay of the samples, including greater resolution of lifetimes for two of the fulvic acids and greater discrimination among samples based on lifetime profiles across the CZE peaks.

A comparative study of proton and alkaline earth metal binding by humic substances

1994 ◽  
Vol 294 (3) ◽  
pp. 319-327 ◽  
Author(s):  
J.R. Lead ◽  
J. Hamilton-Taylor ◽  
N. Hesketh ◽  
M.N. Jones ◽  
A.E. Wilkinson ◽  
...  
Keyword(s):  
Comparative Study ◽  
Humic Substances ◽  
Metal Binding ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal

scholarly journals Comparative study on humic substances isolated in thermal groundwaters from deep aquifers below 700 m

2012 ◽  
Vol 46 (3) ◽  
pp. 211-224 ◽  
Author(s):  
K. KOV^|^Aacute;CS ◽  
A. G^|^Aacute;SP^|^Aacute;R ◽  
CS. SAJG^|^Oacute; ◽  
P. SCHMITT-KOPPLIN ◽  
E. TOMB^|^Aacute;CZ
Keyword(s):  
Comparative Study ◽  
Humic Substances ◽  
Deep Aquifers
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