A comparison of metalloporphyrin distributions in bitumens from New Albany shale using different extraction solvents

New Albany shale was extracted by Soxhlet and batch methods with solvents commonly used for bitumen extraction. The ground shale (- 200 mesh) was extracted with toluene, toluene-methanol (7:3 v/v), dichlorethane-methanol (7:3 v/v), chloroform, and pyridine and the resulting bitumens were separated into nickel (Ni2+) and vanadyl (NO2+) porphyrin aggregates, using liquid and thin-layer chromatography. The VOP and NiP aggregates were analyzed by EIMS. The distributions (carbon number ranges and abundances) of the DPEP (or CAP), etio and other porphyrin series were compared for the different bitumen extraction methods investigated and the implications for metalloporphyrin geochemistry are discussed in this paper. Differences between the NiP and VOP propyrin distributions and variations in the DPEP (CAP)/etio ratio are discussed in relation to solvent-substrate-porphyrine interactions