Detection of 1-hydroxypyrene in urine by direct fluorometric analysis on a solid sorbing phase. Validation and application of the method to biological monitoring of PAH-exposed persons

Abstract

A new method for the detection and quantification of 1-hydroxypyrene (1-OHPy) in the urines of persons exposed to polycyclic aromatic hydrocarbons (PAH) has been evaluated. The method is based on extraction/concentration of the analyte onto a small element cut into tabs from an extraction disk (ENVI-Disk trade mark C18 from Supelco) combined with front-face synchronous fluorescence detection and direct quantification on the solid sorbent element. The limit of detection for 1-OHPy was estimated to be about 0.03-0.04 micro g/L, a value which is significantly lower than the pyrene metabolite concentration commonly found in unexposed to weakly PAH-exposed persons ( approximately 0.1-0.3 micro g/L). A quantification based on only one standard addition has been adopted and the method was validated both by testing analyte recovery using a known amount of a commercially available pyrene metabolite and by comparing the results with those obtained by high-performance liquid chromatography (HPLC). The results were very close to the HPLC results, the largest deviations being attributed to variations or defects in the stirring system, the rate stability of which was found to be of major importance for the reproducibility and reliability of the measurements. The applicability of the method was further tested by analyzing 1-OHPy in the urine of a volunteer exposed to various automobile traffic zones. The results confirm previous findings which lead to the conclusion that urinary concentrations of PAH metabolites are influenced more by smoking habit than by exposure to urban atmospheric pollution. Thus, the method appears to be an alternative to the usual method based on HPLC. Moreover it presents some advantages, being simple to operate and requiring relatively low-cost instruments.