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Quantification of Humic and Fulvic Acids in Humate Ores, DOC, Humified Materials and Humic Substance-Containing Commercial Products
Published on: March 18, 2022
Compositional differences between soil humic acids extracted by various methods as evidenced by photosensitizing and
E Gieguzynska1, A Amine-Khodja, O A Trubetskoj
1Department of Physics, University of Agriculture, ul. Janosika 8, 71-424 Szczecin, Poland.
Chemosphere
|February 24, 2009
Summary
Different humic acid (HA) extraction methods impact their photosensitizing properties. The neutral sodium pyrophosphate (L-HA) method yielded HAs with enhanced singlet oxygen production and long-wavelength fluorescence.
Area of Science:
- Soil Science
- Photochemistry
- Organic Geochemistry
Background:
- Humic acids (HAs) are complex organic macromolecules found in soil.
- Their extraction methods can influence their chemical properties and functions.
- Understanding these influences is crucial for soil science and environmental applications.
Purpose of the Study:
- To investigate how different extraction techniques affect the photosensitizing capabilities of humic acids.
- To characterize the impact of extractants on the elemental composition, functional groups, and photophysical properties of HAs.
Main Methods:
- Isolation of HAs from Elliott soil using three distinct methods: 0.1M NaOH (EI-HA), neutral 0.1M Na(4)P(2)O(7) (L-HA), and combined NaOH/Na(4)P(2)O(7) (NP-HA).
- Analysis of HAs for elemental composition, functional acid groups, absorption/emission spectra, and electrophoretic characteristics.
- Assessment of singlet oxygen production using furfuryl alcohol (FFA) as a scavenger.
Main Results:
- The L-HA fraction exhibited higher aromaticity, oxygenation, long-wavelength fluorescence, and lower molecular size with high electrophoretic mobility compared to EI-HA and NP-HA.
- L-HA demonstrated a 1.25- to 1.6-fold higher rate of FFA photooxygenation, indicating superior photosensitizing activity.
- Photochemical and electrophoretic measurements effectively distinguished the effects of different HA extraction procedures.
Conclusions:
- The extraction method significantly influences HA photosensitizing properties, with the neutral pyrophosphate method yielding more photosensitive fractions.
- Low molecular weight, ionized humic macromolecules contribute substantially to photosensitization and long-wavelength fluorescence.
- Photochemical and electrophoretic analyses are valuable tools for evaluating differences in HA extraction efficacy.
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