Biomonitoring of urinary hydroxy metabolites of polycyclic aromatic hydrocarbons: development and validation of an headspace solid-phase micro extraction gas chromatographic-mass spectrometric method.

Hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) can be used as biomarker of PAHs exposure. A headspace solid phase micro-extraction method for the simultaneous determination of 1- and 2-hydroxynaphthalene, 2- and 9-hydroxyfluorene and 1-hydroxypyrene in human urine was developed, optimized and validated in our laboratory. In order to increase their volatility, analytes were submitted to in-situ derivatization with acetic anhydride prior to extraction. A diethoxydiphenylsilane fiber was used. Optimization of the parameters affecting extraction (i.e. extraction time and temperature and salt addition) was performed using an experimental design. Regression models and desirability functions allowed to find the conditions providing the highest global response of the investigated analytes. Then, validation was carried out in terms of limit of quantitation (LLOQ), precision, accuracy, recovery and stability, following the guidelines for the validation of bioanalytical methods. Finally, the method was applied to the determination of OH-PAHs in urine samples of coke-oven workers.