Are the Traditional Concepts of the Structures of Humic Substances Realistic?

Burdon, J.

doi:10.1097/00010694-200111000-00004

Cited by 155 publications

(105 citation statements)

References 79 publications

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“…A new view has emerged, however, which reconciles observations of macromolecular size to MSbased observations of low molecular weight. The new view describes NOM and humic substances as a dynamic, noncovalent association of small, recognizable biological molecules in various stages of decomposition (Hedges et al 2000;Burdon 2001;Wrobel et al 2003;Sutton and Sposito 2005;Smejkalova and Piccolo 2008). A similar aggregation behavior has been observed in noncovalent oligomers in fossil fuels (Piccolo et al 2002;Mullins et al 2008).…”

Section: Introductionmentioning

confidence: 82%

Electrospray and photoionization mass spectrometry for the characterization of organic matter in natural waters: a qualitative assessment

Hockaday

Purcell

Marshall

et al. 2009

Limnology & Ocean Methods

255

214

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Fourier‐transform ion cyclotron resonance mass spectrometry (MS) has demonstrated potential to revolutionize the fields of limnology and chemical oceanography by identifying the individual molecular components of organic matter in natural waters. The use of MS for this purpose is made possible by the electrospray technique which successfully ionizes polar, nonvolatile organic molecules. Another recently developed ion source, atmospheric pressure photoionization (APPI), extends MS capabilities to less polar molecules. This article presents early results on the application of APPI MS to natural organic matter. We compare APPI MS and electrospray MS data for dissolved organic matter from Lake Drummond (Virginia, USA). Collectively, electrospray and APPI MS identify more than 6000 molecular species to which we assign unique molecular formulas. Fewer than 1000 molecular species are common to both electrospray and APPI mass spectra, indicating that the techniques are highly complementary in the types of molecules they ionize. Access to a broad range of molecules provided by combining APPI and electrospray has prompted a qualitative analysis. The goal is to assess the extent to which molecular MS data correspond with elemental (CHNOS) and structural characteristics determined by combustion elemental analyses and 13C nuclear magnetic resonance (NMR). Because the data obtained by these different methods are not directly comparable, we propose a novel data analysis procedure that facilitates their comparison. The bulk elemental composition calculated from electrospray MS data are in close agreement (± 15%) with values determined by combustion elemental analysis. APPI and electrospray MS detect protein contributions in agreement with 13C NMR (6 wt %) but underestimate carbohydrates relative to 13C NMR. Nevertheless, MS results agree with NMR on the relative proportions of noncarbohydrate compounds in the organic matter: lignins > lipids > peptides. Finally, we use a molecular mixing model to simulate a 13C NMR spectrum from the MS datasets. The correspondence of the simulated and measured 13C NMR signals (74%) suggests that, collectively, the molecular species identified by APPI and electrospray MS comprise a large portion of the organic matter in Lake Drummond. These results add credibility to electrospray and APPI MS in limnology and oceanography applications, but further characterization of ion source behavior is fundamental to the accurate interpretation of MS data.

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Section: Introductionmentioning

confidence: 82%

Electrospray and photoionization mass spectrometry for the characterization of organic matter in natural waters: a qualitative assessment

Hockaday

Purcell

Marshall

et al. 2009

Limnology & Ocean Methods

255

214

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“…Fatty acids are a major component of lipids in soils, originating from microorganisms (n-C 4:0 to n-C 26:0 ) and waxes of plants and insects (n-C 26:0 to n-C 38:0 ) (Schnitzer et al, 1986). Burdon (2001) reported that lipid in the A horizon were dominant at C-25 and C-27. Wiesenberg et al (2004) found that the lipid extracted from various agricultural soils distributed broadly, from C-13 to C-37.…”

Section: Characteristics Of Ha Lipid Char and Coated Charmentioning

confidence: 99%

Effects of humic acid and lipid on the sorption of phenanthrene on char

Wen

Huang

et al. 2009

Geoderma

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“…However, Burdon (2001) pointed out the humification could also occur in plants that did not contain lignin. We have reasons to believe that cellulose serves as a sole substrate can promote the formation of HS or their essential component.…”

Section: Introductionmentioning

confidence: 99%

Compositions and properties of microbial residues formed by three single species fungi and mixed strains in cellulose-containing liquid media

Wang

Dou

Yu³

et al. 2014

J. Soil Sci. Plant Nutr.

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The microbial residues, due to their closely connection with humic substances (HS), aroused our considerable interest. The method of shake-flask in liquid culture was adopt to accumulate them, in which the cellulose served as the sole C source. The microbial suspensions including Trichoderma viride (Tv), Aspergillus niger (An), Penicillium (P) and mixed strains (Ms) were inoculated into the cellulose culture fluid respectively. The incubation was performed for 70 days at a constant temperature of 28 ºC. The results showed that different microbial treatments had different effects on the C turnover in the cellulose fluid, among which Ms performed the most effective role in accumulating microbial residue and consuming organic C of cell metabolic product, Tv followed. As compared to cellulose, large amounts of inorganic N in the fluid could be transferred into the organic N components of residue. In the mean time, the proportion of aromatic rings could be increased at the cost of losing O-containing groups. Specifically, the degrees of condensation were enhanced by Tv and An, however their degrees of oxidation were inhibited. On the contrary, the P and Ms treatments had a significant advantage in the oxydative degradation of cellulose. Although some intermediate products (polysaccharides, phenolic compounds, carboxylic groups and syringyl units etc.) of HS could be detected in the microbial residues treated by Tv and An, their organic molecules did not still achieve the polymerization degree of real HS.

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Are the Traditional Concepts of the Structures of Humic Substances Realistic?

Cited by 155 publications

References 79 publications

Electrospray and photoionization mass spectrometry for the characterization of organic matter in natural waters: a qualitative assessment

Electrospray and photoionization mass spectrometry for the characterization of organic matter in natural waters: a qualitative assessment

Effects of humic acid and lipid on the sorption of phenanthrene on char

Compositions and properties of microbial residues formed by three single species fungi and mixed strains in cellulose-containing liquid media

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