Solid Phase Extraction for 1-Hydroxypyrene as a Biomarker of Occupational Exposure to PAHs Prior to High Performance Liquid Chromatography

Abstract

<em>Urinary 1-hydroxypyrene is frequently used as a major metabolite and biological indicator of the overall exposure to polycyclic aromatic hydrocarbons. In this study, solid phase extraction was appropriately conditioned with regard to sample pH,</em> <em>sample concentration, loading flow rate, elution solvent, washing solvent, sample volume and sorbent mass. Octadecyl silica cartridge (C₁₈) was used as solid phase adsorbent and showed to be an efficient phase in simplifying sample preparation for1-hydroxypyrene. Methanol extracted analyte from spiked urine gave a clean sample for reverse-phase HPLC-florescence. In the developed solid phase extraction conditions (sample pH: 5, sample concentration: 10 </em><em>m</em><em>g/l, washing solvent: distilled water, eluent: methanol, sample volume: 200 ml sample flow rate: 10 ml/min), the extraction recovery exceeded 99.96%, achieving detection limit of 0.02 </em><em>m</em><em>g/l. The extraction factors (sample pH, sample concentration, washing solvent , eluent , sample volume and sample flow rate), were evaluated statistically and also the procedure was validated with three different pools of spiked urine samples at low, medium , and high sample concentrations and showed a good reproducibility over six consecutive days as well as six within-day experiments. All coefficients of variations were less than 3.1%. Finally, urinary 1-hydroxypyrene of industrially exposed workers was also measured, using the appropriate conditions obtained in this study, in which,</em> <em>the amount of the compound of interest in the total exposed subjects was significantly higher than those of non-exposed.</em>