COMPLEXING CAPACITY OF DIFFERENT MOLECULAR WEIGHT FRACTIONS OF SEDIMENTARY HUMIC SUBSTANCES
| Autor: | D. Centioli, Nicoletta Calace, Marco Pietroletti, Bianca Maria Petronio, Marta Letizia Antonelli |
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| Rok vydání: | 2001 |
| Předmět: |
chemistry.chemical_classification
Chromatography Molecular mass Biochemistry (medical) Clinical Biochemistry chemistry.chemical_element Peptide Aromaticity complex mixtures Biochemistry Oxygen Analytical Chemistry Ion selective electrode chemistry Electrochemistry Molar mass distribution Molecule Humic acid Spectroscopy Nuclear chemistry |
| Zdroj: | Analytical Letters. 34:989-1002 |
| ISSN: | 1532-236X 0003-2719 |
| DOI: | 10.1081/al-100103608 |
| Popis: | In this paper we studied the complexing capacity of different molecular weight fractions of humic substances, subdivided into humic (HA) and fulvic acids (FA), extracted from Arno river sediment. Humic acids are characterised by a high degree of aromaticity and a low nitrogen content whereas fulvic acids display aliphatic features and are characterised by a number of oxygen and nitrogenous functional groups such as carboxylic, alcoholic and/or phenolic and peptide groups. The higher degree of condensation of humic acids than fulvic acids is confirmed by their different molecular weight distribution; HA molecules are characterised by a narrow range of molecular weights while fulvic acids are distributed over a wider range of molecular weights. The complexation capacity for HA and FA increases with increasing pH value and at the same pH value the CC for HA and FA is equal even if structural features and molecular weight distribution are different. Moreover, the calorimetric measurements relative to fulvic a... |
| Databáze: | OpenAIRE |
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