Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)

Abstract

Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as char and soot. PyC is ubiquitous in the environment due to its long persistence, and its abundance might even increase with the projected increase in global wildfire activity and the continued burning of fossil fuel. PyC is also increasingly produced from the industrial pyrolysis of organic wastes, which yields charred soil amendments (biochar). Moreover, the emergence of nanotechnology may also result in the release of PyC-like compounds to the environment. It is thus a high priority to reliably detect, characterize and quantify these charred materials in order to investigate their environmental properties and to understand their role in the carbon cycle.Here, we present the benzene polycarboxylic acid (BPCA) method, which allows the simultaneous assessment of PyC's characteristics, quantity and isotopic composition ( 13 C and 14 C) on a molecular level. The method is applicable to a very wide range of environmental sample materials and detects PyC over a broad range of the combustion continuum, i.e., it is sensitive to slightly charred biomass as well as high temperature chars and soot. The BPCA protocol presented here is simple to employ, highly reproducible, as well as easily extendable and modifiable to specific requirements. It thus provides a versatile tool for the investigation of PyC in various disciplines, ranging from archeology and environmental forensics to biochar and carbon cycling research.

Root litter decomposition slows with soil depth

“…Benzene polycarboxylic acids (BPCA) were used as a proxy for pyrogenic C in the soil samples and were measured according to Wiedemeier et al (2016Wiedemeier et al ( , 2013. The BCPA yields were directly reported as BPCA-C (%SOC), without the use of a conversion factor.…”

“…The BCPA yields were directly reported as BPCA-C (%SOC), without the use of a conversion factor. Performance and high reproducibility were checked by measuring samples in triplicates and simultaneously running external standards (Wiedemeier et al, 2016).…”

A New Perspective on the Apparent Solubility of Dissolved Black Carbon

“…BC was quantified and characterized in all samples using the BPCA method (Dittmar, 2008;Ding et al, 2013;Wiedemeier et al, 2016). For leachate samples, where DOM was isolated via solid phase extraction, aliquots of the DOM-containing MeOH elute were transferred to 2 mL glass ampules and the MeOH evaporated under a stream of N 2 gas.…”

“…Additional clean-up steps were also required for the BC analysis of solid samples in order to remove metals and other interfering compounds prior to BPCA analysis (Schneider et al, 2010. The particulate BPCA procedure has been described in detail by Wiedemeier et al (2016). Briefly, dry sample (∼2 mg) was directly transferred to 20 mL glass ampules.…”

Online quantification and compound‐specific stable isotopic analysis of black carbon in environmental matrices via liquid chromatography‐isotope ratio mass spectrometry

“…Black carbon was quantified and characterized in all samples using the BPCA method (Dittmar ; Ding et al ; Wiedemeier et al ). For DOM samples isolated via PPL solid phase extraction (Congo River, Mississippi River, and Gulf Stream), aliquots of the DOM‐containing methanol elute (∼ 0.5 mg‐C equivalents unless otherwise specified) were transferred to 2 mL glass ampules (Wheaton pre‐scored gold band ampules) and the methanol evaporated under a stream of Ar gas.…”