Radiocarbon measurements of black carbon in aerosols and ocean sediments

Masiello, C. A.; Druffel, Ellen R. M.; Currie, Lloyd A.

doi:10.1016/s0016-7037(01)00831-6

Cited by 78 publications

(60 citation statements)

References 29 publications

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“…A 14 C-depleted standard, hexane soot (Akhter et al 1985;Goldberg 1985;Hammes et al 2007) was also used to estimate modern C ex . Environmental BC standards that contained a silicate and metal matrix, including urban dust aerosol NIST Standard Reference Material (SRM 1649a) (National Institute of Standards and Technology 2001;Masiello et al 2002), NIST Standard Reference Material marine sediment (SRM 1941b), and US Geological Survey Green River Shale (Abbey 1983; Gladney and Roelandts 1988;Govindaraju 1994) were used to estimate modern C ex . To observe the matrix effect in marine sediments samples, wood char was added to SRM 1941b that had previously been baked in a muffle furnace for 2 hr at 550 C to remove organic carbon.…”

Section: Black Carbon Standardsmentioning

confidence: 99%

Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices

2013

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ABSTRACT. Extraneous carbon (C ex ) added during chemical processing and isolation of black carbon (BC) in environmental matrices was quantified to assess its impact on compound specific radiocarbon analysis (CSRA). Extraneous carbon is added during the multiple steps of BC extraction, such as incomplete removal of solvents, and carbon bleed from the gas chromatographic and cation columns. We use 2 methods to evaluate the size and  14 C values of C ex in BC in ocean sediments that require additional pretreatment using a cation column with the benzene polycarboxylic acid (BPCA) method. First, the direct method evaluates the size and  14 C value of C ex directly from the process blank, generated by processing initially empty vials through the entire method identically to the treatment of a sample. Second, the indirect method quantifies C ex as the difference between processed and unprocessed (bulk)  14 C values in a variety of modern and 14 C-free or "dead" BC standards. Considering a suite of hypothetical marine sedimentary samples of various sizes and  14 C values and BC Ring Trial standards, we compare both methods of corrections and find agreement between samples that are >50 µg C. Because C ex can profoundly influence the measured  14 C value of compound specific samples, we strongly advocate the use of multiple types of process standards that match the sample size to assess C ex and investigate corrections throughout extensive sample processing.

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Section: Black Carbon Standardsmentioning

confidence: 99%

Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices

2013

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“…It is based on the refractory nature of soot carbon, and it begins with an isothermal oxidation stage, designed to oxidize more labile organic species, as well as their pyrolysis products (char). This approach was inspired by thermal oxidation studies of Cachier et al (1989) and Gustafsson, et al (1997), and the wet chemical oxidation method of Wolbach and Anders (1989) which was subsequently applied to RMs by Masiello et al (2002). In addition to the thermal oxidation studies of Cachier et al (1989), and Gustafsson et al (1997), a method for OC elimination in an oxidizing environment to minimize artificial (pyrolytic) char was developed by Lavanchy et al (1999) contemporaneously with the development of the TOK method.…”

Section: Analytical Techniquesmentioning

confidence: 99%

On the isolation of elemental carbon (EC) for micro-molar <sup>14</sup>C accelerator mass spectrometry: development of a hybrid reference material for <sup>14</sup>C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

Currie

Kessler

2005

Atmos. Chem. Phys.

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Abstract. The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic ( 14 C) speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of "soot" (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14 C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the "truth" was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence ( 14 C in PAH, EC) of measurement validity . Components of the new Hybrid RM (DiesApple), however, have known 14 C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14 C, and its major compositional component is EC; SRM 1515 (Apple Leaves) has the 14 C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure.The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the Correspondence to: L. A. Currie (lloyd.currie@nist.gov) EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of the TOK method substantially reduced the transfer of artifact char to the RC fraction, improving isolation capabilities; (3) the Hybrid RM was not equal to the sum of its parts, with matrix interactions inducing premature loss of EC which, however, could be quantified and minimized; (4) the three-stage TOK method provided a superior capability for carbonate quantification at the submicromolar level, with "reagent-free" removal of carbonate-C from EC -essential for low-level EC-14 C AMS.

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“…These pyrogenic particles play important roles in a multitude of geochemical processes. For instance, BC may be an important component of sedimentary carbon preservation (Goldberg 1985;Gustafsson and Gschwend 1998;Masiello and Druffel 1998;Dickens et al 2004) and thereby constitutes a valuable record of the global fire history (e.g., Bird and Cali 1998). Sorption of aromatic compounds to BC is 10 to 1000 times stronger than to nonpyrogenic sedimentary organic matter (e.g., Bucheli and Gustafsson 2000;Accardi-Dey and Gschwend 2002;Jonker and Koelmans 2002;Cornelissen and Gustafsson 2004) and frequently governs the environmental distribution of many organic pollutants (Gustafsson et al 1997;Gustafsson and Gschwend 1997;Dachs and Eisenreich 2000;Persson et al 2002;Ribes et al 2003).…”

mentioning

confidence: 99%

“…The wet chemical pretreatment-wet chemical oxidation (wet-wet) methods (e.g., Wolbach and Anders 1989;Lim and Cachier 1996;Verardo 1997;Masiello et al 2002;Song et al 2002) have an advantage over thermal oxidation methods: there is a lower risk of charring. However, the extensive handling of samples in liquid solutions may lead to losses of BC particles, which, due to their hydrophobic character, tend to adsorb to inner surfaces of test tubes and to the water-air interface (e.g., Gélinas et al 2001b).…”

mentioning

confidence: 99%

“…Another disadvantage with wet chemical oxidation is that the oxidative strength (i.e., cutoff between BC and non-BC) is more difficult to control than in thermal oxidation as it depends on many factors such as concentration of chemical oxidant, type of oxidant applied, and reaction time. Also, the wet chemical oxidation techniques may be extremely time consuming (e.g., Wolbach and Anders 1989;Masiello et al 2002).…”

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confidence: 99%

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Quantification of sedimentary black carbon using the chemothermal oxidation method: an evaluation of ex situ pretreatments and standard additions approaches

Elmquist

Gustafsson

Andersson

2004

Limnology & Ocean Methods

103

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The highly condensed products and residues of incomplete combustion of biomass and fossil fuel termed black carbon (BC) partake in a multitude of important geochemical processes. However, ambiguity persists because different quantification methods give highly variable results, leaving it unclear whether this reflects method difficulties or that different methods simply mirror different parts of the BC spectrum. Introducing additional wet chemical ex situ pretreatment steps (Gélinas et al. 2001b), to a commonly applied chemothermal oxidation (CTO) method led to large handling and transfer losses of hydrophobic diesel-soot BC (NIST SRM-2975). The resulting yield of soot BC spiked to a coastal marine and a freshwater sediment was only 6 ± 1% and 70 ± 4%, respectively, for the entire ex situ procedure. Instead, a standard addition approach yielded statistically significant linear returns of incremental soot BC additions. The slopes suggested that 51 ± 6% and 78 ± 6% of the added soot BC was accounted for in the marine and freshwater sediment, respectively. The lower recovery of soot BC in the marine sediment is likely caused by chloride enhancing the contact between BC surfaces and mineral oxides, catalyzing the BC oxidation. A consequential lowering of the oxidation energy from 375°C to 360°C resulted in increased soot BC yields of 75 ± 7% and 97 ± 3% in the marine and freshwater sediments, respectively. The standard addition approach suggests a native "soot BC-like" concentration of 0.48 mg BC/g dry weight (soot BC/total organic carbon = 0.03) in the bioturbated marine sediment from Kosterfjord, Skagerrak and 6.2 mg BC/g dry weight (soot BC/TOC = 0.10) in the heavily polluted Rhine River sediment.

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Radiocarbon measurements of black carbon in aerosols and ocean sediments

Cited by 78 publications

References 29 publications

Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices

Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices

On the isolation of elemental carbon (EC) for micro-molar <sup>14</sup>C accelerator mass spectrometry: development of a hybrid reference material for <sup>14</sup>C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

Quantification of sedimentary black carbon using the chemothermal oxidation method: an evaluation of ex situ pretreatments and standard additions approaches

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Radiocarbon measurements of black carbon in aerosols and ocean sediments

Cited by 78 publications

References 29 publications

Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices

Extraneous Carbon Assessments in Radiocarbon Measurements of Black Carbon in Environmental Matrices

On the isolation of elemental carbon (EC) for micro-molar &lt;sup&gt;14&lt;/sup&gt;C accelerator mass spectrometry: development of a hybrid reference material for &lt;sup&gt;14&lt;/sup&gt;C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

Quantification of sedimentary black carbon using the chemothermal oxidation method: an evaluation of ex situ pretreatments and standard additions approaches

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On the isolation of elemental carbon (EC) for micro-molar <sup>14</sup>C accelerator mass spectrometry: development of a hybrid reference material for <sup>14</sup>C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure