Laboratory evaluation of a potential diesel fuel interference in the determination of polycyclic aromatic compounds...

Road pavers are exposed to asphalt fumes through dermal contact, inhalation, or ingestion. These fumes contain polycyclic aromatic compounds (PACs), a class of compounds including polycyclic aromatic hydrocarbons (PAHs). The PAHs include compounds such as pyrene and benzo(a)pyrene and a large number of other compounds of known or suspected carcinogenicity. To estimate dermal deposition of asphalt fume particulate matter, polypropylene sampling patches can be worn on a worker's inside wrist. Diesel fuel used for cleaning can splash onto the dermal sampler. Exposed dermal patches were solvent extracted and PACs estimated in the extract using a modification of NIOSH Method 5800. The final solution was analyzed by high pressure liquid chromatography (HPLC) with a fluorescence detector using an excitation wavelength of 270 nanometers and an emission wavelength of 415 nanometers. The PACs were concentrated on a C-18 reverse phase guard column but not separated so that they could be measured expediently as a group. In this study we examined whether deposited diesel fuel interferes with the HPLC determination of PACs. We characterized the effect of diesel fuel contamination over broad ranges of both analyte and interferent. Two drops, or approximately 100 microL, of diesel fuel on the dermal samplers caused an overestimation of the concentration of polycyclic aromatic compounds (PACs). In the range of PACs determined in our field study (0 to 54 microg per sample), these errors could have exceeded 100%. Because 100 microL of deposited diesel fuel produced a clear visual "wetness," this observation can serve as one of the criteria for sample rejection. Sampling media must be examined carefully for visible contamination to prevent bias in the measurement of PACs deposited from asphalt fume.