title: Amorphous and condensed organic matter domains: the effect of persulfate oxidation on the composition of soil/sediment organic matter.
abstract: The composition of amorphous and condensed soil/sediment organic matter (SOM) domains was investigated for one soil sample and four sediment samples. These samples were oxidized with persulfate to remove amorphous SOM, before and after which the composition of SOM was studied by thermogravimetric analysis, pyrolysis-GC/MS, and cross polarization magic angle spinning 13C-NMR. Comparison of the SOM composition before and after oxidation showed that condensed SOM was more thermostable and less polar than amorphous SOM. Condensed SOM was relatively low in O-alkyl C and carboxyl C and it was likely to contain only small amounts of labile organic components (carbohydrates, peptides, fatty acids). Apart from these general characteristics, the composition of the condensed and amorphous domains appeared to be highly dependent on the origin and nature of the SOM investigated. Condensed domains in relatively undecomposed SOM were enriched in aliphatic C, whereas condensed domains in relatively weathered SOM were enriched in aromatic C. Altogether, the compositional changes upon persulfate oxidation were similar to the compositional changes upon humification, which supports the idea that weathered SOM is more condensed than the original material.
authors.affiliation: Environmental Technology Department, Wageningen University, The Netherlands.
authors.forename: Chiel
authors.initials: C
authors.lastname: Cuypers
authors.forename: Tim
authors.initials: T
authors.lastname: Grotenhuis
authors.forename: Klaas G J
authors.initials: KG
authors.lastname: Nierop
authors.forename: Elena Maneiro
authors.initials: EM
authors.lastname: Franco
authors.forename: Adrie
authors.initials: A
authors.lastname: de Jager
authors.forename: Wim
authors.initials: W
authors.lastname: Rulkens
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009930:Organic Chemicals / Q000032:analysis; D010084:Oxidation-Reduction; D012987:Soil
chemical_list: D002247:Carbon Isotopes; D009930:Organic Chemicals; D012987:Soil