The objective of this study is to identify important organic sulfur-containing compounds in the Argonne Premium Coals and in selected, separated coal macerals. In-source, desorption/pyrolysis high resolution mass spectrometry is being used to characterize the volatile species of whole coals, macerals, and their extracts. To examine the possibility of secondary reactions and undesirable selectivity, the MS data is compared to data from direct techniques, XANES and XPS. The MS results con-elate very well which supports the suggestion that the species seen are indigenous to the original sample. Therefore, specific structural assignments to the sulfur species can be made. Quantitative speciation of organic sulfur in coals has been accomplished by both XANES and XPS with what appears to be good reliability. Mass spectrometry approaches provide more detailed molecular information, but suffer from problems with sampling. In the past we have found it difficult to isolate aliphatic sulfur compounds by thermal desorption or pyrolysis due to their thermal transformation to aromatic species. However, recently we have found that with in-source pyrolysis the occurrence of secondary reactions is reduced significantly. Results from both a selected setof the Argonne Premium Coal Samples and a set of three macerals from the Listen-Stockton coal (APCS 7) are discussed
