Black carbon assessment using benzene polycarboxylic acids: Limitations for organic-rich matrices

Kappenberg, Arne; Braun, Melanie; Lehndorff, Eva; Amelung, Wulf

doi:10.1016/j.orggeochem.2016.01.009

Cited by 74 publications

(62 citation statements)

References 24 publications

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“…Previous studies have shown BPCAs to be primarily derived from charred material (Dittmar, 2008;Roth et al, 2012), especially for pyrogenic organic matter formed at high temperatures (Schneider et al, 2010). However, a recent study points to a potentially non-pyrogenic source for some BPCAs (Kappenberg et al, 2016). Since our DBC concentrations are derived from an accumulated total of all BPCAs (including B3CAs and B4CAs, which have been shown to be produced in small quantities from non-pyrogenic organic matter; Kappenberg et al, 2016), the overestimation of DBC is possible.…”

Section: Contrasting the Quantification Of Dbc With Mass Spectral Datmentioning

confidence: 86%

“…However, a recent study points to a potentially non-pyrogenic source for some BPCAs (Kappenberg et al, 2016). Since our DBC concentrations are derived from an accumulated total of all BPCAs (including B3CAs and B4CAs, which have been shown to be produced in small quantities from non-pyrogenic organic matter; Kappenberg et al, 2016), the overestimation of DBC is possible. However, since B5CA and B6CA (presumed to be exclusively pyrogenic; Kappenberg et al, 2016), give the most weight in converting BPCA amounts to DBC concentrations (Dittmar, 2008) the slight overestimation of DBC would not significantly change the results or interpretation of the current study.…”

Section: Contrasting the Quantification Of Dbc With Mass Spectral Datmentioning

confidence: 98%

“…Since our DBC concentrations are derived from an accumulated total of all BPCAs (including B3CAs and B4CAs, which have been shown to be produced in small quantities from non-pyrogenic organic matter; Kappenberg et al, 2016), the overestimation of DBC is possible. However, since B5CA and B6CA (presumed to be exclusively pyrogenic; Kappenberg et al, 2016), give the most weight in converting BPCA amounts to DBC concentrations (Dittmar, 2008) the slight overestimation of DBC would not significantly change the results or interpretation of the current study. The BPCA and FT-ICR/MS methodologies for detecting DBC across the combustion continuum are fairly wellunderstood, but not definitively constrained (Masiello, 2004).…”

Section: Contrasting the Quantification Of Dbc With Mass Spectral Datmentioning

confidence: 99%

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A New Perspective on the Apparent Solubility of Dissolved Black Carbon

2017

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Black carbon (BC), pyrogenic organic matter generated from the incomplete combustion of biomass, is ubiquitous in the environment. The molecular structures which comprise the BC pool of compounds are defined by their condensed aromatic core structures polysubstituted with O-containing functionalities (e.g., carboxyl groups). Despite the apparent hydrophobicity of BC molecules, a considerable portion of BC is translocated from terrestrial to aquatic systems in the form of dissolved BC (DBC). However, the specific biogeochemical mechanisms which control the transfer of BC from the land to the water remain elusive. In the current study, the apparent solubility of DBC was inferred from octanol-water partition coefficients (K ow ) modeled for proposed DBC structures with varying degrees of polycondensation and polar functionality. Modeled K ow values indicated that DBC molecules with small aromatic ring systems and high degrees of hydrophilic functionality may be truly solubilized in the aqueous phase. However, large and highly condensed DBC structures yielded high K ow values, which suggested that a considerable portion of the DBC pool which has been quantified in aquatic environments is not truly dissolved. We hypothesized that other DOM components may act as mediators in the solubilization of condensed aromatic molecules and serve to increase the solubility of DBC via hydrophobic, intermolecular associations. This hypothesis was tested through controlled leaching experiments to determine whether the mobilization of DBC from particulate soils and chars became enhanced in the presence of DOM. However, we observed that characteristics inherent to each sample type had a greater influence than added DOM on the apparent solubility of DBC. In addition, the direct comparison of molecular marker (benzenepolycarboxylic acids) and ultrahigh resolution mass spectral data (FT-ICR/MS) on leachates obtained from the same set of soils and char did not show a clear overlap in DBC quantification or characterization between the two analytical methods. Correlations between FT-ICR/MS results and BPCA were not significant possibly due to differences in the methodological windows and/or small sample size. Our results were unable to provide evidence in support of proposed hydrophobic interactions between DOM and DBC, suggesting that other physical/chemical mechanisms play important roles in the dissolution of BC.

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Section: Contrasting the Quantification Of Dbc With Mass Spectral Datmentioning

confidence: 86%

Section: Contrasting the Quantification Of Dbc With Mass Spectral Datmentioning

confidence: 98%

Section: Contrasting the Quantification Of Dbc With Mass Spectral Datmentioning

confidence: 99%

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A New Perspective on the Apparent Solubility of Dissolved Black Carbon

2017

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“…It is also unclear if the BPCA method quantifies pyC, exclusively. The method may result in some non-pyrogenic DOC (such as humic substances) being identified as pyrogenic (Kappenberg et al, 2016;Zimmerman and Mitra, 2017). Aside from the potential for false positives, other difficulties arise from the choice of conversion factor and methods used to convert measured BPCA-C of a sample to the amount of ConAC.…”

Section: Pyrogenic Carbon Quantification Methodsmentioning

confidence: 99%

“…More recently, it was suggested that even aromatic rings with aliphatic side chains (e.g., retene) can produce BPCA-C (Ziolkowski et al, 2011). Perhaps this is why Kappenberg et al (2016) observed BPCA production (even B6CA) from pyC-free corn stalks (Zea mays) and leaves of pepper plants (Capsicum annuum), when enough sample was processed (>8.7 mg C). This may also explain why, using total BPCA as an indicator, the greatest concentrations of "pyDOC" have been reported for peat-influenced sloughs and rivers that contain large amounts of humic-like DOM (Ziolkowski and Druffel, 2010;Jaffé et al, 2013).…”

Section: Non-pyrogenic Bpca Productionmentioning

confidence: 99%