Analysis of Black Carbon in Sediments and Soils Using Multi-Element Scanning Thermal Analysis (MESTA).

Analysis of black carbon (BC) is still a critical issue in the carbon cycle research due to the lack of a standardized methodology. This study was initiated to investigate the feasibility of quantifying BC in solid samples using a multi-element scanning thermal analysis (MESTA) method. The MESTA method determines the C and N contents of a sample, with respect to their thermal stability, over the entire organic carbon (OC)/BC continuum. There is a good separation of the BC and the non-BC materials in the MESTA thermograms. Differentiation between BC and OC can be made with a criterion justified by the C thermal stability and the associated N content. The suggested BC criterion in this study is the carbonaceous materials that have peak carbon volatilization temperature ≥550 ^oC in the MESTA. Charring seemed not a problem in the determination of BC with the MESTA method probably because the char produced was not thermally stable enough to be classified as BC. Comparison of the MESTA method to the International BC Ring Trial methods shows that the BC contents of the Chernozem, the Vertisol and the SRM 1649a urban dust are in the mid-range, while those of the wood char and the grass char are in the lower end among the ring trial methods. This study also reveals significant amount of N that is structurally associated with the thermally stable carbonaceous materials. This study shows that MESTA is a sensitive, reproducible and convenient method for BC analysis in environmental samples.