Polyurethane foam chips combined with liquid chromatography in the determination of unmetabolized polycyclic aromatic hydrocarbons excreted in human urine

A method suitable for the determination of unmetabolized polycyclic aromatic hydrocarbons (PAHs) excreted at trace levels (ng/L) in human urine for the monitoring of exposure of the general population to PAH contamination was developed. PAHs were determined, after enrichment by solid‐phase extraction on polyurethane foam (PUF) chips, by HPLC with fluorescence detection. Different parameters affecting analyte extraction to the PUF, including urine salting‐out and organic additives, and optimization of conditions for clean‐up and desorption have been investigated. Optimized conditions were 40 mL acidified urine sample, added with magnesium sulfate, tetrahydrofuran and a 2 cm³ PUF chip, and extracted by shaking at 30 rpm for 1 h at ambient temperature. Desorption was performed, after a clean‐up step with diluted sodium hydroxide, using a small amount of diethyl ether. The recovery of PAH congeners from spiked urines was >90% in the 2–100 ng/L range; the detection limit was 0.1–0.5 ng/L, depending on the considered PAH congener; day‐to‐day precision, at 50 ng/L native PAH content, was CV = 10–20%. The proposed technique provides a simple, economical and effective procedure for the determination of trace amounts of unmetabolized PAHs excreted in human urine spot samples. Copyright © 2006 John Wiley & Sons, Ltd.