Laboratory Generated Bitumen Fumes Under Standardized Conditions. Clean-up Scheme and Ion Trap GC-MS Analysis of VOC, Semi-Volatile and Particulate PAH and PASH

Abstract

This article reports the applicability of an efficient clean-up and enrichment procedure for the determination of polycyclic aromatic compounds (PAC) including polycyclic aromatic hydrocarbons (PAH) and polycyclic aromatic sulfur heterocyclic hydrocarbons (PASH) in the gas and particulate phases in raw bitumen and bitumen fumes by gas chromatography-ion trap mass spectrometry. The scheme includes a liquid-liquid partition to eliminate the aliphatics, a solid phase extraction on SiO₂ cartridge to remove the polar compounds and an HPLC fractionation to isolate the aromatic fraction. The purified extract enables the determination of PAH profile from 2 to 7 rings including their methyl derivatives and 3 carcinogenic benzonaphthothiophene isomers. The reproducibility of the method was estimated by analyzing 6 bitumen replicates and is around the 30% overall uncertainty or less. In bitumen fumes generated at 170°C under standardized conditions, VOC and semi-volatile PAH were sampled with XAD-2 tubes and were also determined in six replicates. The VOCs are mainly monoaromatic derivatives (4% of fumes) and aliphatics essentially from C₆ to C₁₇ (27%). With regards to the particulate phase PAC, the coefficients of variation from 6 replicates are 5–24% for PAH and 6–10% for PASH. Data on VOC and PASH represent new contribution in the characterization of bitumen fumes.

Keywords:

• asphalt
• bitumen fumes
• volatile organic compounds
• polycyclic aromatic hydrocarbons
• polyaromatic sulfur heterocyclic hydrocarbons
• characterization

ACKNOWLEDGMENTS

The authors would like to thank Philippe Boiteux for his greatly appreciated technical assistance.

Notes

^A Other ions at m/z 134.