Determination of polycyclic aromatic sulfur hydrocarbons (PASH) in petroleum asphalt fractions and their fumes by high-performance liquid chromatography with pulsed amperometric detection

Asphalt binders are primarily composed of aromatic hydrocarbons, but they also contain sulfur compounds that play a critical role in the chemical aging of the matrix. This study presents the development and validation of a high-performance liquid chromatography method with pulsed amperometric detection (HPLC-PAD) for the determination of polycyclic aromatic sulfur heterocycles (PASHs) in asphalt fractions and emissions. A mixture of 32 PASH standards was grouped into 20 analytically distinguishable peaks under optimized conditions. The method enabled quantification of PASHs at sub-ppm levels in both volatile (0.08–5.37 mg kg⁻¹) and nonvolatile (0.02–0.38 mg kg⁻¹) fractions. The presence of specific PASHs, including methyl- and dimethyl-substituted thiophenes, was also qualitatively confirmed by APPI-MS/MS analysis. These findings demonstrate the potential of the HPLC-PAD method as a reliable and cost-effective approach for screening sulfur-containing polyaromatic compounds in complex asphalt matrices.