Development of a chemiluminescent enzyme immunoassay for urinary 1-hydroxypyrene

A chemiluminescent enzyme-immunoassay for urinary 1-hydroxypyrene has been developed and optimized. The enzymatic activity of horseradish peroxidase-labeled tracer was measured with an enhanced chemiluminescent system and the results were compared with those from conventional colorimetric detection. The method fulfilled all the requirements of accuracy and precision and the detection limit was 0.001 pmol/well, which enabled analysis in less than 1 µL urine. Subjects working in the center of Bologna who were exposed daily to vehicular exhaust gas were studied. Their urinary 1-hydroxypyrene concentrations were compared with the levels of benzo(a)pyrene in air particulate matter. Urinary 1-hydroxypyrene, which ranged from 0.5 to 10 nmol L–1, correlated poorly with the concentration of benzo(a)pyrene in air particulate matter, which ranged from 5 to 140 ng m–3. No significant effect of vehicle exhaust gas exposure was observed among the different groups of subjects working in different areas of the town. Thus, at a relatively low level of exposure 1-hydroxypyrene does not seem to be a sensitive biomarker of exposure to polycyclic aromatic hydrocarbons.