English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/81866
Share/Impact:
Statistics
logo share SHARE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:
Title

Chemical heterogeneity of humic substances: characterization of size fractions obtained by hollow-fibre ultrafiltration

AuthorsChristi, I.; Knicker, Heike ; Kögel-Knabner, I.
Issue DateDec-2000
PublisherWiley-Blackwell
CitationEuropean Journal of Soil Science 51 (4): 617–625 (2000)
AbstractTo investigate the chemical heterogeneity of humic substances in relation to molecular size, fulvic and humic acids were extracted and purified from the surface horizon of a Humic Gleysol in northern Switzerland. A fractionation scheme using hollow-fibre ultrafiltration cartridges was developed and used to obtain four size fractions of the humic acid with nominal molecular weight ranges > 300 kDa, 100–300 kDa, 30–100 kDa, and 10–30 kDa. The fulvic acid and all humic acid fractions were characterized by size exclusion chromatography, elemental analysis (C, H, N, S), as well as spectroscopic techniques including UV-VIS, CP-MAS 13C-NMR, FT-IR, and fluorescence spectroscopy. Clear chemical differences between the humic acid size fractions were observed. Smaller size fractions of the soil humic acid contained more chargeable functional groups and a larger percentage of aromatic carbon than the larger size fractions. Conversely, the percentage of aliphatic carbon increased with increasing apparent molecular weight. The chemical composition of the smallest humic acid fraction differed clearly from the fulvic acid fraction, despite similar apparent molecular size and carboxyl carbon content. Small humic acids contained much more aromatic carbon and less aliphatic carbon than the fulvic acid fraction. Apparently, humic size fractions differ in their chemical composition, which can have important implications for their environmental behaviour.
Publisher version (URL)http://dx.doi.org/10.1111/j.1365-2389.2000.00352.x
URIhttp://hdl.handle.net/10261/81866
DOI10.1111/j.1365-2389.2000.00352.x
ISSN1351-0754
E-ISSN1365-2389
Appears in Collections:(IRNAS) Artículos
Files in This Item:
File Description SizeFormat 
Acceso restringido.pdf15,38 kBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.