A cleanup method using solid phase extraction for the determination of organosulfur compounds in petroleum asphalt cements

•Cleanup method for the determination of model organosulfur compounds in asphalt cements.•Use of a commercially available aminopropyl stationary phase for solid phase extraction.•Different classes sampled including aliphatic and aromatic compounds.•Use of differential pulse voltammetry in non-aqueous media for the cleanup monitoring.•Characterization of the model compounds in asphalt samples after the cleanup method.

A solid phase extraction method using the aminopropyl stationary phase was described for the determination of organosulfur compounds in petroleum asphalt cements by liquid chromatography. Thiophenes, sulfides, sulfoxides and sulfones were used as model compounds of organosulfur species present in asphalts. The cleanup of the samples was studied by differential pulse voltammetry in non-aqueous media and the characterization of the asphalt samples was performed by liquid chromatography equipped with a tandem mass spectrometry using atmosphere pressure photoionization. Under optimum conditions, a linearity was achieved for the extraction of sulfur compounds between 0.1 and 3.5 mg*L−1 for most analytes studied and the correlation coefficient ranged from 0.991 to 0.997. The recovery of the organosulfur compounds using aminopropyl stationary phase ranged from 65.37 to 114.85% for butyl sulfoxide and thianaphthene, respectively. The developed cleanup method allowed the identification and determination of at least seven organosulfur compounds in the asphaltic matrices.

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