Microwave-assisted combustion to produce benzene polycarboxylic acids as molecular markers for biochar identification and quantification

Abstract Biochar is a promising carbon dioxide removal (CDR) technology for climate change mitigation. Current procedures its determination are lengthy, labor-intensive, and difficult to conduct. Benzene polycarboxylic acids (BPCA) the most molecular markers identification quantification of biochar quality as they specifically represent stable polyaromatic backbone biochar. Therefore, using BPCA method, stability and, thus, C sequestration potential could be used CDR accounting. The current method relies on specific high-pressure digestion apparatus, which not available around world. aims present work were (i) compare conventional nitric acid oxidation with microwave-assisted technique optimize conditions in such way that previous results comparable future ones, (ii) significantly reduce time soil samples 8 h develop suitable routine produces reproducible results. For this purpose, control sample series prepared different temperature–time-program. Obtained compared values both individual whole dataset separately. To ensure representativeness results, addition various properties, we included two reference materials into our data set, one without (wheat flour) sample. Our showed at 170 °C can substituted by microwave reaction system (CEM Mars6) 190 1 h. further condition needs strictly matched, because, otherwise, over- or underestimation quantity and/or will consequence. goal less time-consuming extraction from was achieved reducing method. However, disadvantage new five times more material chemicals needed analysis, original